Volume 34 (Supplement 3) May 2007

1st Annual Meeting

The Canadian Association for Neuroscience /

Association canadienne de neuroscience

TORONTO, ONTARIO, MAY 23-25, 2007

ABSTRACTS

Abstract Legend First number - Indicates Abstract number Letter - Indicates day and time of presentation A - Thursday, May 24 Morning, B - Thursday, May 24 Afternoon C - Friday, May 25 Morning, D - Friday, May 25 Afternoon

Last series of numbers - Indicates room & board number 100 series - Giovanni Room, 200 series - Terrace Room 300 series - St. Lawrence Room, 400 series - St. George Room, Example: 1 A201 - Abstract number 1, being presented on Thursday, May 24 Morning, in Terrace Room on board #1

Published by the Canadian Journal of Neurological Sciences. The Canadian Journal of Neurological Sciences does not assume any responsibility or liability for any errors in the abstracts.

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THE CANADIAN JOURNAL OF Neurological Sciences LE JOURNAL CANADIEN DES Sciences Neurologiques

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THE CANADIAN ASSOCIATION FOR NEUROSCIENCE / ASSOCIATION CANADIENNE DE NEUROSCIENCE

TABLE OF CONTENTS

3 Cognition and Behaviour 101 Homeostatic and Neuroendocrine Systems 24 Development 107 Other 35 Disorders of the Nervous System 110 Sensory and Motor Systems 66 Education 123 Techniques in Neuroscience 66 Excitability, Synapses and Glia: Cellular Mechanisms 127 Author Index

COGNITION & BEHAVIOUR 2 B102 THE EFFECTS OF ACUTE ALCOHOL INTOXICATION ON IMPLICIT AND EXPLICIT LEARNING 1 B101 Iris M. Balodis*, Ingrid S. Johnsrude, Mary C. Olmstead. Department of PERCEIVING AN OBJECT’S MATERIAL PROPERTIES Psychology & Centre for Neuroscience Studies, Queen's University, THROUGH DYNAMIC SOUND ACTIVATES VENTRAL Kingston, Ontario OCCIPITOTEMPORAL AND INFERIOR PARIETAL CORTICES Stephen R. Arnott, Jonathan S. Cant, Melvyn A. Goodale. CIHR Group for The impact of alcohol on implicit, emotional learning is not well Action and Perception, Department of Psychology, The University of Western understood, partly because factors ranging from family history, drug use and Ontario task demands influence these processes. The Conditioned Pattern Preference (CPP) task provides a more ecologically valid means to investigate implicit Knowledge of an object’s material composition (i.e., what it is made of) cognition in the lab because it has low demand awareness and relies on alters how we interact with that object. Seeing the bright glint or hearing the associative learning with nonlinguistic cues that were previously paired with metallic crinkle of a foil plate for example, confers information about that reward. This study examined the effects of acute alcohol intoxication on plate before we have even touched it. In a previous study (Cant & Goodale, implicit learning using the CPP task in 89 intoxicated and 69 sober young 2007) it was shown that visually attending to an object’s material properties adults. Information on individual drug use, family history, impulsivity and as opposed to its shape or color, elicited greater hemodynamic activity in alcohol expectancies was also collected. Alcohol intoxication affected ventral occipitotemporal regions. In the present fMRI study, we investigated explicit, but not implicit, learning on the CPP. In addition, participants who whether there are comparable brain areas that are sensitive to material reported a positive family history of addiction (FH+) or individual properties derived from sound alone. Using a passive visual adaptation recreational drug use did not exhibit a preference for cues previously paired paradigm we first localized an area in the right parahippocampal region that with reward. Preference formation on the CPP task recruits motivational was most selective for material as compared to shape or colour properties of neurocircuitry, an effect that is unaltered by alcohol. Group differences in objects. In a separate series of runs, participants were presented with two- implicit emotional learning on this task may represent neurocognitive second normalized sound clips and asked to categorize them as either differences in individuals at risk for addiction. Material (crumpling styrofoam, plastic, tinfoil or paper), Noise (scrambled versions of each of the material sounds), or Human sounds (coughing, yawning, snoring or throat clearing). Although functional analyses of the 3 B103 auditory data within the visual material region did not reveal any discernable REPRESENTATION OF COMPLEX OBJECTS IN THE MACAQUE modulation, expanding the region to include all of parahippocampal cortex TEMPORAL LOBE REVEALED BY FMRI revealed an area that was selective for Material sounds as compared to Noise Bell, Andrew H, Hadj-Bouziane, Fadila, Ungerleider, Leslie G., Tootell, or Human sounds. In addition, a voxel-wise analysis of the auditory Roger B.H., 1Laboratory of Brain and Cognition, NIMH/NIH, Bethesda, experiment also revealed greater ‘Material’ activity in left lateral inferior MD, USA, 2 Athinoula A. Martinos Ctr. for Biomed. Imaging, Massachusetts parietal area, perhaps reflecting the action-related nature (i.e., crumpling) of General Hospital, Charlestown, MA, USA the sounds. Our findings point to an important multimodal role for the parahippocampal region in the analysis of material properties, and are It is increasingly clear that a functional organization of stimulus consistent with the notion that the medial aspect of the ventral pathway is properties exists in primate inferior temporal (IT) cortex. Early physiological specialized for processing the material properties of objects. work suggested that this organization is based on variations in physical stimulus properties. However, recent fMRI work has interpreted such differences in terms of object category (i.e., semantic) properties. To explore

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these two hypotheses and the evolutionary generality of human fMRI results, schizophrenia patients. Moreover, subchronic PCP produced an enhanced we measured contrast-agent enhanced fMRI signals in 3 awake fixating response to amphetamine in rats, reminiscent of the effect of amphetamine in macaques, at 3T. The subjects maintained central fixation while blocks of schizophrenic patients; however, rats with extensive memory task training stimuli from the following categories were presented: monkey faces, body failed to show this effect. Results provided some support for the hypothesis parts, familiar objects, familiar scenes, and scrambled images. Face and that PCP treatment may lead to memory impairments. (Funded by OMHF) scene images were presented both upright and inverted, in separate blocks. As in previous studies, these categories activated distinct (though partially overlapping) regions of cortex. Images of faces (relative to all other 5 B105 categories) activated right anterior IT cortex, and a bilateral area farther EFFECTS OF FOOTSHOCK STRESS ON THE REINSTATEMENT posterior within the STS. Body part images activated cortex adjacent and OF COCAINE SEEKING FOLLOWING EXTENDED POST-STRESS medial to face-selective regions. Objects and scenes activated areas in the DELAY PERIODS inferior temporal gyrus, hippocampus, intraparietal sulcus, and specific Zenya Brown & S. Erb. Centre for the Neurobiology of Stress, Departments prefrontal regions. Comparing the responses to upright vs. inverted images of Life Sciences and Psychology, University of Toronto at Scarborough, revealed an inversion effect for faces but not places; responses to inverted Toronto faces were reduced compared to upright faces. These results revealed that stimuli similar to each other (e.g. faces) activated more focal regions of Footshock stress robustly reinstates drug seeking in rats when tests for cortex, compared to stimuli that were visually less similar (e.g., scenes, reinstatement are conducted immediately following termination of the objects). To measure the sensitivity to individual stimulus properties, an stressor. However, it has not previously been determined whether delays in additional experiment was performed in which blocks of single exemplars the opportunity for drug seeking following exposure to footshock affects were presented for each category. For each category, we found exemplar- reinstatement of drug seeking. Examining the effects of post-stress delay selective voxels, ranging from very few (for faces) to larger proportions (for periods on reinstatement of drug seeking is of interest, since individuals with objects). Thus, macaque IT cortex shows a modular organization similar to a history of drug dependence do not always have access to seek out or use that reported in human fMRI, currently interpreted in terms of object drugs immediately following a stressful life event. The objective of the category specificity. However, our single-image tests suggest that a present study was to determine for how long footshock stress remains functional organization for lower-level stimulus properties also exists, within effective in inducing relapse to cocaine seeking following its termination, presumptive category-selective regions. and whether the context in which post-stress delay periods are experienced affects the magnitude of reinstatement. Rats were allowed to self-administer cocaine (1.0 mg/kg per infusion) for 8-10 days. Following a 7-day drug-free 4 B104 period, drug-taking behaviour was extinguished and, subsequently, animals BEHAVIOURAL EFFECTS OF SUBCHRONIC PHENCYCLIDINE were tested for reinstatement in response to intermittent footshock stress (20 IN RATS: TESTS OF AMPHETAMINE-STIMULATED min; 0.8 mA). In a first series of experiments, animals were tested for LOCOMOTOR ACTIVITY AND MEMORY reinstatement following a 0-, 20- or 60-min post-stress delay period. In a Jonathan Beuk1, Michael van Adel1, James N. Reynolds2 and Richard J. second series of experiments, animals were tested for reinstatement Beninger1,3. Depts. 1Psychology, 2Pharmacology and Toxicology and following a 40- or 60-min post-stress delay period that was given in either the

3Psychiatry, Queen’s University, Kingston self-administration (SA) chamber or homecage (HC). Footshock reliably and robustly reinstated cocaine seeking following post-stress delays of up to 40 Schizophrenia is a crippling disease that is characterized by positive minutes. No differences in response levels were observed between animals symptoms represented as an excess in normal functioning (e.g., that spent the delay period in the SA chamber versus HC. Thus, within a hallucinations or delusions), negative symptoms represented as a deficiency limited time window, footshock stress is effective in reinstating cocaine in normal functioning (e.g., social withdrawal, apathy) and cognitive seeking when testing is delayed following termination of the stressor. problems (e.g., disorganized thoughts, memory impairments). Phencyclidine Overall, the findings are consistent with earlier work from this laboratory, in (PCP) administration produces schizophrenia-like psychotic symptoms in which central injections of the pharmacological stressor, corticotrophin- humans and exacerbates psychotic symptoms in schizophrenic patients. PCP releasing factor, were effective in inducing reinstatement of cocaine seeking is an n-methyl-D-aspartate (NMDA) glutamatergic receptor antagonist. after extended post-injection delays. The findings will be discussed in terms These observations have led to the proposal that NMDA receptor of a contextual conditioning account of reinstatement. hypofunction may contribute to schizophrenic symptoms. This suggested the hypothesis that PCP treatment may lead to memory impairments. To test this hypothesis, male Sprague-Dawley rats were treated subchronically with PCP 6 B106 (4.5 mg/kg, i.p. twice a day for 7 consecutive days) or saline and tested 7 COMMON AND DISTINCT FEATURES OF SLOW CORTICAL days following the last injection. In the first experiment, rats were tested in a OSCILLATION DURING NATURAL SLOW-WAVE SLEEPAND locomotor activity task followed by a watermaze memory task. The KETAMIN-XYLAZINE ANESTHESIA subchronic PCP (n = 12) group showed a significant increase in amphetamine Chauvette, Sylvain* and Timofeev, Igor. Centre de recherche Université (1.5 mg/kg)-stimulated locomotor activity similar to the increased sensitivity Laval Robert-Giffard, Québec to amphetamine seen in schizophrenia; however, they did not significantly differ in watermaze task response latency when compared to controls (n = While sleep and anesthesia are different states, they have common traits 12). In experiment 2, rats were extensively trained to make correct arm and may share common mechanisms. Based on this notion, anesthetized entries in a double-y maze that consisted of a spatial task followed by an animals have been used to study sleep mechanisms at levels spanning from a alternation task before receiving drug treatment. Groups were subsequently single cell to large and distributed neuronal networks. During natural slow- tested in the double-y maze task and for locomotor activity. After subchronic wave sleep cortical neurons display a slow oscillation (< 1 Hz) consisting in PCP administration, rats (n = 12) exhibited a significantly greater number of an alternation between active and silent states. Ketamine-xylazine anesthesia overall arm entry errors when compared to controls (n = 9) in the double-y induces a similar oscillation in cortical neurons and it is often used as a model maze memory task; however, the two groups did not differ significantly in of slow-wave sleep because of similar electrographic appearance. Here we the locomotor activity task. These findings suggest that subchronic blockade asked: What is common, and what is different, in the mechanisms of sleep of NMDA receptors leads to impaired memory of a previously learned task and anesthesia? To answer this question, we used simultaneous multi-site in rats, similar to the cognitive impairments observed in human field potentials recordings (16) and simultaneous multi-site intracellular

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recordings both, in naturally sleeping and anaesthetized animals. Analysis of 8 B108 dynamics of local field potential recordings revealed that activity started at LEFT VERSUS RIGHT HEMISPHERE DUAL TASK deeper locations and in some superficial locations, but appeared later in the INTERFERENCE ON FACE PROCESSING middle of the cortex. The current-source density analysis revealed that during Jesse MacKewn*, Paul Brewster and Jennifer Steeves. Department of both slow-wave sleep and ketamine-xylazine anesthesia there are strong Psychology and the Centre for Vision Research, York University, Toronto sinks in the upper layers during silent states and sources in deeper layers. Upon transition to active states, the picture reverses to the opposite: sinks in A variety of evidence shows that the right hemisphere of cortex is critical the deeper and sources in the upper layers. During active states, the sources for mediating face recognition. Some research also suggests that there are and sinks are generally weaker and more variable in both space and time than gender differences in face recognition ability (women are better than men) during silent states. The sinks and sources that are present in upper layers in and that men show more asymmetric brain activation in favour of the right natural sleep are weaker in anaesthetized animals. Intracellular activities hemisphere than women. Here we examined the role of gender in a dual task revealed the same tendency in both preparations. Although in a given set of paradigm during face processing. If faces are processed primarily in the right neurons each neuron located at any depth could be leading a particular cycle, hemisphere, then face recognition should be adversely affected because of most of the cycles were led by deeply lying neurons and the extent of interference with left finger tapping since they are both using resources in the variability of neuronal activities onsets was similar in both preparations. right hemisphere of the brain when compared to right hand tapping. Ninety Finally, extracellular unit recordings from the same neurons during sleep and right handed students were tested on their ability to recognize faces during anesthesia demonstrated that both periodicity and firing rates during concurrent unimanual finger tapping. There were 6 tapping conditions ketamine-xylazine anesthesia were higher. We conclude that ketamine- compared to a no tapping condition— either left or right hand tapping during xylazine-induced slow oscillation reproduces major patterns of sleep slow a) encoding, b) recognition or c) both encoding and recognition of faces. In oscillation. Exceptions from this rule are stronger rhythmicity and higher each condition, participants were shown three faces once for 3000 ms and firing rates of cortical neurons. Supported by CIHR and NSERC were required to learn these faces. Participants were then asked to recognize the three faces they had just learned among 6 distracter faces. Participants made a vocal response and accuracy and latency were measured. Overall, 7 B107 men were slightly faster than women at recognizing faces. In the no tapping BRAIN AREAS THAT MEDIATE PERCEPTION AND NAME control condition, women were somewhat better at recognizing faces than SELECTION DURING OBJECT NAMING men which is consistent with previous research. Women, however showed a Philippe A Chouinard, Brendan F Morrissey, Stefan Köhler, Melvyn A greater reduction in face recognition with left finger tapping during the Goodale. CIHR Group on Action and Perception, Department of Psychology, recognition and encoding/recognition conditions compared to right finger University of Western Ontario, London tapping. Men showed the largest reduction in performance with left finger tapping during the encoding/ recognition condition and with right finger Naming an object requires one to first perceive the object and then select tapping during encoding and encoding/recognition. These findings suggest a name. Disruption to any one of these processes will impair a person’s that overall men were more affected by dual task interference in either ability to name objects. The use of functional neuroimaging to parcellate hemisphere but that women were most affected by the dual task when it object-naming areas into areas responsible for perception and name selection required neural resources from the right hemisphere for face recognition. has proved challenging. Areas responsible for each of these processes may depend on each other and naming may result in top-down influences in perceptual areas. Our study used a slow event-related design while 9 B109 measuring neural activity in the brain with fMRI. We presented two images CYCLICAL AND SLEEP-LIKE ALTERNATIONS OF BRAIN STATE in succession that were either of the same object (same exemplar), different UNDER URETHANE ANAESTHESIA objects with the same name (different exemplar), or different objects with Clayton T. Dickson, Alto S. Lo, Elizabeth A. Clement, Alby Richard. different names (control). This was done while participants named and did Department of Psychology and Centre for Neuroscience, University of not name objects. The design enabled us to assume that responses to the first Alberta object would be equal in a given naming condition and that any difference in BOLD would be driven by differences in effects induced by the second Alternations in brain state during unconsciousness are a normal feature of object. We also measured reaction times during BOLD acquisition. We sleep, but are not a characteristic feature of general anaesthesia. Previously, found repetition suppression induced by shared physical features in the left we have shown that rats maintained under urethane anaesthesia demonstrate posterior-fusiform gyrus (pFus), differential contributions of the left a spontaneous and cyclical alternation of brain state that is remarkably ventrolateral-prefrontal cortex (VL-PFC) and areas in the medial-frontal similar in a variety of ways to the REM/non-REM cycle expressed during cortex in name selection, and top-down influences in the left pFus induced natural sleep. In the present study we performed a comparison of the brain from naming objects. We demonstrate further relationships between state effects under urethane to three other common veterinary anaesthetics behavioral priming induced from naming objects and differences in BOLD in (ketamine/xylazine, pentobarbital, and isoflurane) by performing long-term the left VL-PFC. Our study provides insight into which areas play a role in neocortical and hippocampal field recordings in rats. We show that although perception and which play a role in name selection when participants name all anaesthetics promote an increase in slow power at dosages promoting objects. Moreover, the fact that we found an influence of naming on activity anaesthesia, (perhaps equivalent to deep slow wave sleep or in some cases in the left pFus, demonstrates that neural processing in relatively early even coma), only urethane allows the spontaneous alternations between perceptual areas can be influenced by top-down semantic processing. activated and deactivated forebrain EEG patterns that are typical of natural Relationships between task performance and neural activity were found in sleep while still providing a uniformly consistent anaesthetic state. Our areas related to name selection and not in areas related to perception. We results suggest that urethane’s pharmacological action in the brain may speculate that this is because identification involves neural processes in later closely overlap the physiological mechanisms for the maintenance of the stages of object naming. natural sleeping state in rats.

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10 B110 12 B112 EFFECTS OF INTRACCUMBAL AMPHETAMINE ON EMISSION NEURAL MARKERS OF OBJECT SEGREGATION AND OF 50-KHZ VOCALIZATIONS IN INBRED LINES OF LONG- RECOGNITION IN THE HUMAN BRAIN: EVIDENCE FROM EVANS RATS MAGNETOENCEPHALOGRAPHY (MEG) Shannon E.G. Duffus1*, Jeff Burgdorf2, Jaak Panksepp3, and Stefan M. Stephen M. Emrich*, Susanne Ferber, Bernhard Ross. University of Toronto Brudzynski1. 1Department of Psychology and Centre for Neuroscience, - Department of Psychology, Rotman Research Institute - Toronto Brock University, St. Catharines, 2Falk Center for Molecular Therapeutics, Department of Biomedical Engineering, Northwestern University, Evanston, Traditional models of object recognition posit that processing of figure USA, 3Department of VCAPP, Washington State University segregation precedes the identification and recognition of an object. However, recent evidence suggests that some recognition processes may Emission of 50-kHz vocalizations was observed in a number of appetitive occur prior to or simultaneously with segregation. The present research social situations and is regarded as an expression of positive state in rats. delineates the temporal sequence of processing stages involved in figure- Emission of 50-kHz calls is associated with the activity of the mesolimbic segregation and object-recognition. Neural activity was recorded using dopamine system. Rats were taken from three lines of Long-Evans rats (high, magnetoencephalography (MEG) while participants observed moving low, and random), which were selectively bred for high and low emission of displays containing scrambled or intact objects, as well as simple coherent 50-kHz calls induced in response to heterospecific play. Eighteen rats from motion. An event-related synthetic aperture magnetometry (erSAM) the 17th generation of breeding (6 from each line) were implanted with technique was used to identify brain regions of maximal activation in intracerebral cannulae in the shell of the nucleus accumbens. Amphetamine response to the moving objects, and source activity for these regions was (5-10 μg/0.5μl) was unilaterally injected into the accumbens and estimated for each condition. The results demonstrate sources located in ultrasonic vocalizations were recorded for 5 min following a 2 min delay. All regions corresponding to the motion-sensitive MT+, the object-sensitive rats emitted species-typical 50-kHz calls regardless of the situation, line, and lateral occipital cortex (LOC), as well as regions in extra-striate cortex and dose of amphetamine; the calls differed neither in the individual duration, the inferior temporal lobe. At early latencies, activity in MT+ and the LOC frequency nor bandwidth. After injection, a significant increase in the was similar between scrambled and intact objects. This was followed by number of 50-kHz calls (p< 0.01) was observed in a dose-dependent manner. activity in the the inferior temporal lobe. The activity in the inferior temporal However, there was no difference in the number of induced calls among the sources in response to recognizable objects was significantly different from lines. Interestingly, the number of calls emitted by rats of the high line was the activity in response to scrambled forms. Activity in these regions was not significantly different from that of the low line. These preliminary results followed by additional activity in the LOC which also differentiated between suggest that the sensitivity of the mesolimbic dopamine system, as tested intact and scrambled objects. The results provide evidence that recognizable pharmacologically in the accumbens, is similar across the inbred lines. This and scrambled objects are initially processed similarly by extra-striate and study was supported by the NSERC of Canada. lateral occipital cortices. This initial activity is followed by feedback modulation from inferior temporal cortex. Activity in the LOC at later latencies is greater for objects than for scrambled objects. These findings 11 B111 contrast traditional models of object recognition, and suggest that the LOC VERTICAL SHIFTS IN WORK-RESPONSE FUNCTION may initially perform figure-segregation processes. SUGGESTS VULENRABILITY DIFFERENCES TO WHEEL RUNNING ADDICTION Ali Gheidi & Roelof Eikelboom. Department of Psychology, Wilfrid Laurier 13 B113 Univerty, Waterloo Ontario THE GAZE FIXATION ASYMMETRY EXHIBITED BY HUMANS WHEN VIEWING FACES IS INDEPENDENT OF AUDIOVISUAL Wheel running has been postulated as a non-drug model of addiction SPEECH PERCEPTION AND FACIAL ATTRIBUTES (Eikelboom and Lattanzio, 2003). Exploring changes or differences in drug Ian T. Everdell*, Heidi Marsh, Micheal D. Yurick, Kevin G. Munhall, and dose-response functions has been helpful in understanding drug motivation Martin Paré. 1Centre for Neuroscience Studies, 2Biological Communication in addiction. Horizontal shifts in the drug dose-response function Centre, and Departments of 3Otolaryngology, 4Physiology, and 5Psychology, demonstrate the occurrence of drug sensitization and tolerance. Recently, it Queen’s University, Kingston, Ontario has been suggested that vertical differences in drug self-administration dose- response functions are indicative of vulnerability differences to addiction Speech perception under natural conditions requires integration of (Piazza, Deroche-Gamonent et al, 2000). The present study attempted to auditory and visual information. Understanding how a viewer assimilates the replicate Piazza et al., (2000) by exploring a work-response function in wheel information contained in these sensory modalities requires detailed running addiction. Different degrees of friction were applied to running descriptions of the available speech information and the way that information wheels to make them more or less easy to turn. 24 adult male rats were is processed. To better understand how facial information is gathered, we permitted to run with low, medium or high friction, alternated on a daily basis quantified the distribution of gaze fixations of humans performing an for 36 days, at which point running had plateaued. Although running was audiovisual speech perception task with dynamic talking faces. We examined decreased when the degree of friction increased, the work exerted by rats the degree of gaze fixation asymmetry to determine whether left-right biases (distance run x friction) showed an inverted U function similar to that evident were a result of asymmetries in the face stimulus itself or of strategies of the in the drug dose-response function. Rats were separated into high and low viewer. Most participants preferentially fixated the right side of the faces, runners based on a medium split of the final 24 h running amount on the low suggesting a right visual field bias; this bias was present in the first fixations friction condition. In comparing high and low running rats, it was observed following stimulus onset and persisted with horizontally mirrored faces, that their work-response function did not differ horizontally (shifting to the different talkers, and static faces. Participants showed stronger fixation right or left), but rather showed a vertical shift, as high runners acquired their asymmetries when viewing dynamic faces, in comparison to static faces or high levels of running over the first part of the study. Therefore, it could be face-like objects, and especially when their gaze was directed to the talker’s concluded that only some animals have a predisposition to wheel running eyes. Correlation analysis revealed that the magnitude and direction of an addiction, and they work harder across all levels of friction. (This work was individual’s gaze asymmetry during audiovisual speech (i.e., dynamic funded by a NSERC grant to RE.) stimuli) are predicted by the same parameters measured during simple face processing (i.e., static stimuli). Although viewing dynamic faces significantly enhanced speech perception, we did not find any correlation between task performance and fixation asymmetry or between performance and fixation of

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specific facial features. Similarly, asymmetry did not appear to be related to showed similarly high levels of freezing in context A and B, indicating other measures of laterality (handedness and eye-dominance), nor was there generalization across contexts. Again, hippocampal lesions greatly reduced a difference in performance between original and horizontally mirrored freezing levels in this group. Conditioned freezing in either the 1-day and 21- stimuli. Viewing patterns over time were relatively consistent regardless of day lesion groups could not be reinstated by a reminder shock and did not the talker’s face or its orientation: mouth fixation probability increased at show spontaneous recovery when tested one week later. However, both speech onset and decreased at speech offset, but in general, fixations were not lesion groups could be retrained and showed normal performance in the open related to details of the stimulus. These results suggest that asymmetrical field suggesting that the lesioned-mice had no performance deficit related to distribution of gaze fixations reflects the participants’ general face-viewing motor or sensory dysfunction. We further showed that the hippocampal- strategies rather than being a product of asymmetry within the faces lesioned mice were impaired in the hidden version of the water maze, themselves. That these strategies did not predict audiovisual speech therefore validating the effectiveness of the lesion in another behavior task. perception suggests that the process of gathering information from a talker’s These results indicate that discrimination between similar contexts always face involves a large visual span that is independent of the ability to gather requires the hippocampus. Surprisingly, we found no evidence for a graded that information. effect of these lesions on levels of conditioned freezing, suggesting that the hippocampus may also play an extended role in the expression of conditioned fear. 14 B114 ATTENDING TO MIND AND BODY: MINDFULNESS TRAINING REVEALS DISTINCT NEURAL MODES OF SELF-AWARENESS 16 B116 Norman Farb1, Zindel Segal1, Helen Mayberg2, Jim Bean3, Deborah ESTROGEN RECEPTOR α, BUT NOT β, IS INVOLVED McKeon3, Zainab Fatima1, Adam Anderson1;. 1- University of Toronto, 2- IN REGULATING ESTROGEN-INDUCED CONDITIONED TASTE Emory University, 3- St. Joseph's Health Centre AVOIDANCE IN MALE RATS. Melissa A. Fudge, Martin Kavaliers, Klaus-Peter Ossenkopp. Neuroscience Despite of considerable progress specifying the cognitive and neural Graduate Program, The University of Western Ontario, London mechanisms underlying the temporally extended self (e.g., retrieval of personality traits from memory), little is known about the neural mechanisms When estrogen is paired with the consumption of a sucrose solution, rats by which humans monitor momentary selfexperience in the psychological will subsequently display conditioned taste avoidance as indexed by a present. To characterize these two aspects of self-awareness, we used fMRI significant reduction in sucrose consumption. A variety of studies have to examine regional brain activity in individuals before or after 8 weeks of shown that estrogen exerts its many effects through activation of at least 2 training in mindfulness meditation (MT), during 1) “narrative” self-focus estrogen receptor subtypes. However, it is unclear as to which estrogen (NF), characterized by monitoring the self related to enduring traits and 2) receptor subtype, either estrogen receptor alpha (ERα) or beta “experiential” self-focus (EF), characterized by monitoring the self related to (ERβ), is involved in mediating estrogen-induced conditioned taste moment-to-moment experience, while reading personality descriptors. avoidance. The present study examined the contributions of ERα and Novice participants engaged cortical midline self-referential regions (medial ERβ in the production of conditioned taste avoidance in male Long prefrontal cortex, mPFC) to a lesser degree during EF than NF. Following Evans rats. A lickometer apparatus was used to measure changes in sucrose MT, EF resulted in more pronounced and widespread reductions in midline consumption and drinking patterns. In addition, a novel automated open cortical activity, which were replaced by a right lateralized network, field apparatus was used to investigate possible drug-induced sedation and/or comprised of the ventral and dorsal PFC and posterior cortical foci, including anxiety effects. After habituation to the lickometer and adjustment to a water regions associated with viscero-somatic representations (right insula, inferior deprivation schedule, animals were tested on three separate conditioning parietal lobule and secondary somatosensory cortex). Consistent with the days and one vehicle test day. On each conditioning day, animals were importance of mPFC disengagement for EF, functional connectivity analyses injected with either propyl pyrazole triol (PPT,an ERα agonist), demonstrated a decoupling between the right insula and mPFC following but diarylpropionitrile (DPN, an ERβ agonist), 17β-estradiol (E2) or not before MT. These results suggest a fundamental neural dissociation vehicle (10% ethanol- 90% saline) 20 minutes before drinking a sucrose between distinct forms of self-awareness uncovered through mindfulness solution from the lickometer. Immediately following this, animals were training—a mental and bodily self. Focused monitoring of moment-to- placed into the automated open field for 30 minutes. It was found that both moment experience is associated with increased access to right lateralized E2 and PPT significantly reduced sucrose drinking on Conditioning Days 2 neural representations of the bodily self, potentially representing the and 3, and produced a robust conditioned taste avoidance on the vehicle test underlying older substrates and origins of selfhood. day. The ERβ agonist DPN did not significantly reduce sucrose intake compared to vehicle controls on any experimental day. There were no significant drug effects on either locomotor activity or anxiety measures. 15 B115 Together, these results suggest that E2-induced conditioned taste avoidance THE ROLE OF THE HIPPOCAMPUS IN RECENT AND REMOTE is regulated by estrogen’s activation of ERα, and not ERβ. This CONTEXTUAL DISCRIMINATION research is supported by NSERC. Szu-Han Wang, Paul W. Frankland. Neurosciences and Mental Health, Hospital for Sick Children, Toronto; Dept. of Physiology and Institute of Medical Science, University of Toronto 17 B117 The acquisition of contextual fear conditioning depends on the hippocampus. THE EFFECTS OF REACHABILITY AND TOOL USE ON FMRI However, as the contextual fear memories mature, they may become less ACTIVATION IN HUMAN BRAIN REGIONS INVOLVED IN HAND precise. To examine the role of the hippocampus in the maintenance and ACTIONS precision of contextual fear memory, mice were trained in a context *Jason P. Gallivan, Cristiana Cavina Pratesi and Jody C. Culham. discrimination procedure where one context was paired with shock (i.e., A+), Neuroscience Program, The University of Western Ontario, London, ON; whereas another was not (i.e., B-). One or 21 days later, mice received a sham Dept. of Psychology, University of Durham, Durham, UK; Dept. of or excitotoxic hippocampal lesion, and conditioned freezing in contexts A Psychology, The University of Western Ontario, London,m ON & and B were then evaluated one week later. In the 1-day group, the sham Neuroscience Program, The University of Western Ontario, London, ON animals discriminated between contexts, showing higher levels of freezing in A compared to B. Hippocampal lesions abolished this discrimination and Electrophysiological recordings in macaques and neuropsychological greatly reduced freezing levels. In the 21-day group, the sham animals studies in humans have reliably shown that the parietal cortex encodes a

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unique representation of visual space within reach of the arm (peripersonal stream about once per second (combined target rate 0.5 Hz), requiring a sharp space). In particular, previous research from our lab has shown that an area focus of attention on the relevant CF. Trials were 120s in duration and involved in reaching, the superior parieto-occipital cortex (SPOC), is active delivered in blocks separated by a brief rest. In the first half of the attention during the passive viewing of objects placed within reach of the arm. As task participants were asked to press a button to targets in one auditory such, this area appears to encode a potential for action on the object. Here we stream and, in the second half, in the other stream. Behavioral performance used functional magnetic resonance imaging (fMRI) to examine how SPOC was assessed by relating each button press to the immediately preceding encodes object distance from the body. We predicted that SPOC would show target in each stream. SSR was assessed by DFT applied to each 120s block. a preference for objects within reach of the arm, even during passive viewing Behavioral analyses showed orderly response latency distributions when when no action is required. In order to investigate this hypothesis we responses were timed to targets in the attended stream, but random presented 8 subjects with graspable objects at six different locations on a distributions when related to targets in the unattended stream. Subjects platform placed over each subject’s hips. Each subject’s upper right arm was therefore complied with the attentional requirements of the task. Distinctive braced only permitting an arc-like range of movement with their lower arm. 37 Hz and 41 Hz SSRs were generated by each carrier frequency. However, Within single trials of an event-related design subjects were required to SSR amplitude did not track the attention requirement. The findings suggest perform grasping and reaching actions to an object location along the arc of that the spotlight of attention cannot selectively illuminate specific tonotopic reachability, at the point corresponding to the subject’s sagittal midline (H regions in PAC. Our ability to attend to different frequency components of a location). Subjects were also instructed to passively view five object sound may depend on other mechanisms. (Supported by CIHR and NSERC locations: two near locations (N1 and N2) positioned in the right and left of Canada) visual fields, equally eccentric from fixation (such that only the N1 location was within range of the subject’s reach); two middle locations on the left and right (M1 and M2), both positioned at a unreachable further distance; and a 19 B119 far location (F) that was positioned in the right visual field far beyond reach. DISSOCIABLE ROLES FOR NUCLEUS ACCUMBENS Subjects were required to maintain fixation throughout all trials and keep SUBREGIONS IN EFFORT-BASED DECISION MAKING their hand positioned on the nearest edge of the platform in between action S. Ghods-Sharifi*, S. B. Floresco. University of British Columbia trials and during passive viewing trials. A voxelwise conjunction analysis between passive viewing conditions for Animals are constantly faced with decisions involving cost-benefit N1 (within reach) vs. each of the non-reachable locations (N2, M1, M2, F) analyses, assessing which particular course of action is most appropriate so revealed activation within SPOC. This finding suggests that SPOC encodes that the potential reward exceeds the costs. Decisions regarding choosing a objects within reach of the hand as our results cannot be attributed to object larger magnitude of reward that is accompanied by a greater effort are eccentricity (less activation in N2) or visual field (less activation in M2 and mediated by a distributed neural network of anterior cingulate, basolateral F) effects. Furthermore, we also investigated whether SPOC is sensitive to amygdala, and mesoaccumbens dopamine system. Previous studies the enlargement of reachable space with tool use. Subjects in the same investigating the neural mechanisms underlying effort-based decision experimental design performed grasping and reaching with a set of tongs to making have employed a T-maze task in which rats have had the option to objects at a tool (T) location (located in the subject’s midline but further than climb a barrier in one arm to obtain a high reward (HR), or exert no effort by the H location) while passively viewing objects at all other pre-specified choosing an arm without a barrier, receiving a low reward (LR). Although locations (N1, N2, M1, M2, F). In this case, the range of space reachable with earlier studies have investigated the role of nucleus accumbens (NAc) the tool now encompassed passive viewing locations N1, N2, and M1. Using dopamine in this form of decision making, surprisingly there have been no a region of interest approach, analyses in SPOC indeed suggest that object studies assessing the effects of inactivation of different subregions of the locations reachable by the tool are newly encoded as being within reach. NAc regions on these tasks. The present study investigated the role of the NAc core and shell using an automated effort discounting decision making procedure in an operant chamber. The task consisted of 4 discrete blocks of 18 B118 10 trials, whereby rats were given the choice of pressing one lever once to AN INVESTIGATION OF THE FREQUENCY SELECTIVITY OF receive 2 reward pellets (LR) or another lever that delivered 4 pellets (HR) ATTENTIONAL MODULATION OF PRIMARY AUDITORY after a fixed ratio of presses that increased with each block (2, 5, 10, or 20). CORTEX In a subsequent experiment, the delay to receive the LR was equalized to the P.E. Gander, D. Bucarelli, D.J. Bosnyak, L.E. Roberts. Department of time it took the animal to complete the ratio on the HR lever (0.5-7s), to asses Psychology, Neuroscience and Behaviour, McMaster University whether these effects were due to differences in delay to reinforcement. In both experiments, inactivation of the NAc core, but not the shell, reduced the Neurons in the primary auditory cortex (PAC) are targeted by cholinergic preference for the HR lever. These effects were not accompanied by changes projections from the basal forebrain that modulate synaptic plasticity by in motor or motivational functions. Thus, the NAc core, but not shell, is part making neurons more sensitive to their afferent inputs. This suggests that the of a distributed neural circuit that mediates effort-based decision making. basal forebrain system which is corticotopically organized may perform Furthermore, the contributions that NAc core makes to this form of decision some of the functions of an attention mechanism. Consistent with this making are distinct from those which mediated delay-based decision making. hypothesis, we have shown that the amplitude of the 40-Hz auditory steady state response which localizes to the PAC is enhanced by attention. SSR amplitude increased when subjects detected targets in a 1s stream of 40-Hz 20 B120 stimulation compared to conditions in which subjects passively experienced ENCODING OF COMPLEX VISUAL MOTION BY A SINGLE the stimuli. NEURAL PATHWAY The present study investigated whether modulation of the PAC by J.R. Gray, B.B. Guest and D.P. Bakke. Department of Biology, University of attention can be frequency specific. Subjects (n=16) were presented with two Saskatchewan auditory streams differing in carrier frequency (CF) but containing separate targets embedded in each. The two streams (CF either 250 Hz or 4100 Hz) The lobula giant movement detector (LGMD) and its target neuron, the were presented simultaneously at moderate intensities (65 dB SPL) but descending contralateral movement detector (DCMD), constitute one motion amplitude modulated at different rates (37 or 41 Hz, counterbalanced) so that sensitive pathway in the locust visual system that is preferentially sensitive the brain response to each stream could be separated by filtering. Targets to objects approaching on a direct collision course. Previously described were AM pulses of enhanced amplitude that occurred randomly in each LGMD responses to motion stimuli suggest that this pathway should be

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sensitive to approaches of individual objects within a complex visual scene. 22 B122 To test responses to complicated object motion, we presented intact locusts VISUO-TACTILE BINDING IN MIRROR-INDUCED ILLUSORY with compound looming objects while recording from the DCMD. SPACE Presentation of paired objects approaching from different regions of the Vanessa Harrar, & Aliza Sturm. Psychology, Centre for Vision Research, visual field at nonoverlapping, closely timed and simultaneous approach York University intervals were designed to study DCMD responses to multiple looming stimuli. We also presented single objects that deviated from a direct collision The temporal perception of stimuli changes depending on their relative trajectory to test whether DCMD responses encode visual parameters that spatial location. We compared the effect of actual and illusory spatial emulate stimulation during collision avoidance behaviours. Looming separation between components of a bimodal stimulus pair on perceived compound objects evoked characteristic DCMD responses that were similar timing. Subjects were presented with light/touch stimulus pairs with various to size-matched simple objects. Specifically, the time of peak firing was onset asynchronies and were asked to make temporal order judgments (TOJs) consistent with predicted values based on a weighted ratio of the half size of and simultaneity judgments. Using a mirror, we manipulated the perceived each distinct object edge and the absolute approach velocity. For paired spatial location of the stimuli. The left hand’s mirror reflection appeared as approaches the azimuthal position and approach interval affected DCMD an illusory right hand that could be either congruent or incongruent with the firing properties. Moreover the DCMDs responded to individual objects right hand’s true location. The just noticeable differences of the TOJs were approaching within 106 ms of each other. Comparisons between individual significantly smaller than for simultaneity judgments: paradoxically the TOJs and paired approaches revealed that overlapping approaches are processed in of stimuli could sometimes be accurate even when the stimuli were perceived a strongly sublinear manner. Deviations away from a looming trajectory by as simultaneous. While TOJs were affected by the separation of the stimuli single objects evoked a distinct peak in the DCMD firing rate that was in space, simultaneity judgments depended on whether the stimuli were independent of object size or time of deviation. These findings suggest that presented within a particular spatial integration window, suggesting at least this single, motion sensitive pathway is able to encode complex aspects of two temporal coding mechanisms. visual scenes that emulate conditions during production of natural behaviour.

23 B123 21 B121 DIFFERENTIAL RESPONSES TO THE D3 RECEPTOR NICOTINE DEPENDENT AND WITHDRAWN MICE ANTAGONIST U99194 IN DBA/2 VS. C57/B16 MICE TREATED DEMONSTRATE CONDITIONED PLACE AVERSIONS THAT ARE WITH CHRONIC ETHANOL ABOLISHED BY THE DOPAMINE ANTAGONIST ALPHA- S.J. Harrison1*; J.N. Nobrega2. 1 Psychology Dept., University of Toronto, FLUPENTHIXOL Toronto, 2 Neuroimaging Research, Center for Addiction & Mental Health, Taryn Grieder1, Ryan Ting-A-Kee1, and Derek van der Kooy1,2. 1. Institute Toronto of Medical Science, 2. Department of Medical Genetics and Microbiology, University of Toronto Neural mechanisms that underlie behavioural sensitization, the progressive increase in responding to a drug over time, have been postulated Although nicotine is one of the most widely used addictive drugs, the to be similar to those that underlie behavioural pathologies such as substance motivational properties that make it so addictive are largely unknown and the abuse and relapse. A better understanding of these mechanisms could be current practice for characterizing the nicotine abstinence syndrome and its helpful in identifying treatment strategies, particularly in the realm of motivational effects in the mouse is unreliable. The purpose of our work is to pharmacotherapy. When studying the mechanisms of sensitization, most determine whether mice will experience nicotine withdrawal, and if so, what studies have focused on the respective roles of the D1 and D2 dopamine neurobiological substrates are mediating the motivational effects of this receptor subtypes. Recently, there has been evidence to suggest that the D3 withdrawal. We implanted mice with osmotic minipumps containing a high dopamine receptor subtype also plays a role in behavioural sensitization, dose of nicotine (100 mg/kg/day) for 2 weeks and observed them for somatic although its exact function remains largely unknown. We previously and motivational withdrawal upon pump removal. These mice demonstrated observed in our laboratory that D3 receptor knockout mice (D3 KOs) were a nicotine somatic abstinence syndrome that was strongest 8 hours after resistant to the sensitizing effects of ethanol (EtOH) when compared to their pump removal. Furthermore, nicotine dependent mice showed an aversion to wild type littermates. In an effort to observe whether the lack of D3 function the withdrawal-paired side in a conditioned place preference paradigm when has a true effect on sensitization or whether the observed resistance to EtOH conditioned 8 hours after pump removal. Historically, the mesolimbic sensitization in D3 KOs was a compensatory mechanism, we hypothesized dopamine (DA) system is believed to play an important role in the rewarding that temporary blockade of D3 receptors with an antagonist would interfere and aversive aspects of many drugs of addiction, including nicotine. with the development and expression of sensitization to EtOH in normal Therefore we investigated the role of DA in dependent nicotine aversion. mice. In 2 separate strains of mice, one more susceptible to the sensitizing Interestingly, when our nicotine dependent and withdrawn mice were pre- effects of EtOH (DBA/2), and the other more resistant to EtOH sensitization treated with the broad-spectrum DA receptor antagonist alpha-flupenthixol (C57/Bl6), animals received 7 bi-weekly injections of EtOH (2.2 g/kg i.p.) or (0.8 mg/kg, i.p.) under conditions where alpha-flupenthixol produces no saline, followed 10 days later by challenge dose of the D3 antagonist U99194 motivational effects on its own, their conditioned place aversions were (10 mg/kg s.c.). In a second experiment, the 2 strains of mice received abolished. However, naive mice that were administered a single dose of U99194 (10 mg/kg s.c.) co-administered with every EtOH injection (2.2 nicotine (5 mg/kg, s.c.) and conditioned 8 hours later showed a significant mg/kg i.p.). In the first experiment, the D3 antagonist challenge had no conditioned place preference for the acute withdrawal paired side that was significant effect on EtOH sensitization in either strain of mice; however, in not blocked by alpha-flupenthixol. These results suggest that dopamine the second experiment where the co-administration of D3 antagonist receptor activation mediates the aversive motivational affects of nicotine significantly blocked the development of sensitization in DBA/2 mice, withdrawal when animals are in a drug dependent and withdrawn state. C57/Bl6 mice developed sensitization to the D3 antagonist itself. Results of these studies suggest that in addition to having differential effects in two genetically different strains of mice, D3 antagonists do not block the expression of sensitization once it has been induced, but may be useful in preventing the development of sensitization in individuals genetically more susceptible to EtOH sensitization. Support Contributed By: NSERC, OGS and CAMH Research Fund.

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24 B124 /-), DYN (-/-) mice demonstrated a decrease of Nur77 expression compared AFFECTIVE CHRONOMETRY OF SECURITY MOTIVATION to WT mice following AMPH chronic administration. Interestingly, we Andrea Hinds*, Dr. Henry Szechtman, Dr. Erik Woody. Hinds, A., Szechtman, observed increased level of ENK expression in Nur77 (-/-) compared to WT H; Dept. of Psychiatry & Behavioural Neurosciences, McMaster University, type mice in both basal and post-AMPH treatment conditions. Taken Hamilton and Woody, E.; Dept. of Psychology, University of Waterloo, together, these results demonstrated that striatal ENK and DYN are both Waterloo necessary to develop behavioural sensitization. They also suggested that Nur77 involvement in homeostatic regulation of dopaminergic systems A recent theory (Szechtman & Woody, Psychol Review, 111:111-127, probably consist in a complex regulation of ENK and DYN expression. 2004) posits a Security Motivation System (SMS) activated by potential, Finally, they supplied strong evidence of an interaction between the direct rather than by imminent, threat to the individual. SMS coordinates species- and indirect dopaminergic pathways. typical motor activity that probes the environment for danger and includes behaviors such as checking (eg, for the presence of predators) and cleaning (for potential threats from germs, etc). Activation of SMS induces also an 26 C101 affective phenomenological cue of potential danger that is experienced as CROSS MODAL IDENTITY RECOGNITION: THE EFFECTS OF anxiety. We investigated whether a physiological correlate of an activated FACE AND VOICE INTEGRATION ON RECOGNITION SMS would show the expected properties: activation by a relevant stimulus Adria E. N. Hoover* and Jennifer K. E. Steeves. Department of Psychology, and persistence of activity until performance of the appropriate behavior. We Centre for Vision Research, York University, Toronto report here on a paradigm that produces the expected results, a paradigm that can be employed in future studies to investigate the disturbance in SMS Humans have an impressive ability to recognize hundreds of individuals proposed to characterize obsessive-compulsive disorder. Participants were by their face. A similar recognition ability is encountered with individual instructed to contact a high contamination-threat stimulus (diapers appearing voices. How often does one pick up the phone and immediately recognize the soiled). Physiological measures of anxiety—heart rate variability and facial identity of the caller by just the word, “hello”? Here we asked whether EMG activity—were taken prior to, during, and after exposure. Separate bringing the two modalities together, vision and hearing, will result in groups were either permitted to engage in the appropriate behavior (washing) enhanced identity recognition. In addition, females have shown better face or engaged in an irrelevant task. Measures of anxiety were significantly recognition performance compared to men; will this gender bias be higher after exposure to the diapers as compared to baseline resting maintained with cross modal stimuli? We trained 60 participants on 5 sets of recordings. These measures remained significantly elevated in participants female and male identities each. Identities consisted of a visual face image not given an opportunity to wash as compared to those permitted to wash. and a voice sample pair. Face image contrast was reduced so that latency for After hand washing, measures of anxiety returned to baseline. Supported by recognition of the face alone was consistent with latency for voice alone. The CIHR MOP134450. learning phase consisted of three runs of 20s presentations for each of the face images with the matching voice sample. Two practice trials with feedback ensured that participants had learned the faces and voices of their 25 B125 respective identities prior to testing. We tested recognition performance IMPLICATION OF THE TRANSCRIPTION FACTOR NUR77 AND (accuracy and correct latency) in a learned/ novel identity paradigm. There ENDOGENOUS STRIATAL NEUROPEPTIDES ENKAPHALIN AND were five conditions in which face and voices were paired: 1) learned DYNORPHIN IN AMPHETAMINE INDUCED BEHAVIORAL congruent-- learned faces and voices paired correctly; 2) learned SENSITAZATION incongruent– learned faces and voices paired incorrectly; 3) face learned and *Hodler C, Paquet B, Gilbert F, Drolet G, Lévesque D AND Rouillard C. novel voice -- ; 4) novel face and voice learned --; 5) novel face and novel Centre de Recherche en Neurosciences, CHUL, Sainte-Foy, Quebec voice. There was no difference in recognition performance between female and male participants. There were however, significant differences in Several studies suggest that striatal enkephalin (ENK) and dynorphin performance between the conditions. Novel face and voice pairings were (DYN) are important for neuroadaptation following psychostimulant most quickly and accurately recognized. In contrast, novel face/ learned exposure. Other evidences show that nuclear receptors acting as transcription voice pairings were better recognized than novel voice/ learned face pairings. factors are involved in the regulation of dopaminergic pathways. Among This suggests that participants rely more heavily on visual than auditory them, Nur77 seems implicated in adaptation and homeostatic regulation of information when recognizing identity. Finally, unlike identity recognition dopaminergic systems. Therefore, by using mice deficient for the gene Nur77 from a face image alone, women do not show better recognition compared to (Nur77 (-/-)), ENK knockout (ENK (-/-)) and DYN knockout mice (DYN (- men when identity is based on both auditory and visual information. /-)) versus wild type (WT) mice, we investigated the respective role of this particular transcription factor and these two neuropeptides in behavioural sensitization induced by repeated amphetamine (AMPH) administration. 27 C102 WT, Nur77 (-/-), ENK (-/-) and DYN (-/-) mice received a five-day AMPH MANIPULATING PROBABILITY TO INVESTIGATE THE pre-treatment (2.5 mg/kg/day) and were challenged five days later with the RELATIONSHIP BETWEEN OVERT AND COVERT ORIENTING same AMPH dose. Both basal and AMPH-induced locomotor activity were Janis Kan*, Ullanda Niel* and Michael Dorris.. Department of Physiology recorded. Levels of ENK, DYN and Nur77 mRNA were measured by in situ and Centre for Neuroscience Studies, Queen’s University, Kingston hybridization. Basal activity was lower in ENK (-/-) and DYN (-/-) mice than in WT whereas Nur77 (-/-) mice displayed an enhanced basal activity Previous studies investigating the relationship between overt orienting compared to their WT littermates. In response to repeated AMPH injections, (saccadic eye movements) and covert orienting (visuospatial attention) have ENK (-/-) and DYN (-/-) mice failed to show behavioural sensitization often led to contradictory results. Evidence has suggested that these two whereas Nur77 (-/-) mice displayed a higher response to repeated AMPH processes are subserved by either the same, interdependent or independent treatment than WT mice. Biochemical analysis in mice brains showed similar neural mechanisms. For the most part, these studies utilized instructive cues basal expression levels for DYN in WT and ENK (-/-) mice, whereas Nur77 in which to allocate attention then asked if motor preparation follows. We basal expression was higher in ENK (-/-) mice. Following AMPH treatment, examined this issue by taking the opposite approach; that is, saccade ENK (-/-) mice showed an increase of Nur77 and a no change of DYN preparation was first allocated by manipulating the probability of a saccadic mRNA expression whereas WT mice displayed a decrease of Nur77 target being presented to either the left or right and we tested whether concomitant to a slight increase of DYN expression. Contrary to the ENK (- visuospatial attention followed. During a minority of trials, a probe (a ring

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with a gap at the top or the bottom) was presented at different time intervals McMaster Univ.; 3 Dept. of Psychiatry, UBC; 4 Division of Neurology, before the target stimulus. Subjects were required to maintain fixation during Sunnybrook Health Sciences Centre; 5 Dept. of Science & Mathematics, these trials and discriminate the orientation of the gap with a keyboard press. Kettering University, Flint, Michigan; 6 Imaging Research, Sunnybrook Overt orienting- Probability influenced overt orienting; as the probability of Health Sciences Centre the target increased, saccadic reaction time to the target decreased and the proportion of erroneous saccades directed towards a probe stimulus at that Numerous studies have consistently shown that homosexual men have an location increased. In addition, as the time of probe presentation neared time increased prevalence of non-right-handedness and atypical patterns of of target presentation, the proportion of erroneous saccades also increased. hemispheric functional asymmetry compared to heterosexual men (e.g., Covert orienting- Probability influenced covert orienting in a manner similar Lalumiere et al., 2000). Within the general population, non-right-handedness to that of overt orienting; as the probability of the target increased, the in men has been associated with increased size of the corpus callosum (CC), proportion of correct probe discriminations also increased. The proportion of particularly of the isthmus, the posterior region of the callosal body correct discrimination also increased as the time of the probe presentation interconnecting parietotemporal cortical regions (Witelson, 1989). Since neared the time of target presentation. Overall, we also found a positive sexual orientation is associated with hand preference and since hand correlation between behavioural indexes of overt and covert orienting. preference is associated with CC anatomy in men, it was hypothesized that Together, our results suggest that the neural processes subserving overt and sexual orientation in men is associated with callosal anatomy, specifically the covert orienting are either interdependent or the same. (Supported by CIHR) isthmus. Our study focussed on the relationship of CC anatomy and sexual orientation in strongly right-handed men, defined as consistently-right- handed (CRH), in order to control the confound caused by the increased 28 C103 prevalence of non-right-handedness among homosexual men. We predicted A NEURAL NETWORK MODEL THAT ILLUSTRATES HOW THE that CRH homosexual men would have a greater callosal isthmus compared DYNAMIC PROPERTIES OF SPATIAL UPDATING DEPEND ON to CRH heterosexual men. To determine whether this sample of CRH THE TYPE OF SIGNALS USED TO DRIVE THE UPDATING homosexual men differed cognitively from heterosexual men as in the G. P. Keith1,2, J. D. Crawford 1,2,3;. 1 Psychology, York University, Toronto, literature, we administered a battery of tests which assessed spatial and 2 Centre for Vision Research, Centre for Vision Research, Toronto, 3 verbal abilities. Twelve homosexual and ten heterosexual young healthy men Biology and Kinesiology, York University, Toronto underwent MR imaging at Sunnybrook Health Sciences Centre. Area measures of the total midsagittal surface of the hemisphere, the CC and four It is currently believed that remembered visual target locations are stored subdivisions including the isthmus, were made. Independent t-tests revealed in eye-centered coordinates and updated across eye movements. Neuronal that isthmal area was larger in the homosexual group (directional t–test, p = behavior associated with this updating has been observed in brain areas 0.03). Binary logistic regression analysis was undertaken to predict group associated with saccade generation, in the form of transient receptive field membership (i.e., homosexual vs heterosexual) and all anatomic and remapping prior to and during the saccade. The dynamics of this remapping, psychological variables were included in the stepwise (forward selection) however, remain largely unexplored. We trained three 3-layer recurrent analysis. The best-fit model included Left Hand Performance (a measure of neural networks to perform the saccade-related target updating associated manual asymmetry), isthmal area, the Shipley Abstraction score (a measure with the double-saccade task to examine how representations of target of logical reasoning), and Water Level score (a measure of spatial position evolve during this updating. Target position during fixations was perception). This model yielded 96% correct classification (p < 0.001) using represented in the output layer as a hill of activation in a 2-D topographic 85% confidence limits (one heterosexual man was misclassified) and array of units. Network inputs were initial target position, dynamic eye accounted for 84% of the variance. These results suggest that position, and the signal(s) used to drive the updating, which, for the three neuroanatomical structure and cognition are associated with male sexual networks were 1) the initial 'cortical' representation of the saccade target, 2) orientation and add to the evidence of a neurobiological basis in the etiology the dynamic 'brainstem' velocity signal of the saccade, and 3) both. In the of sexual orientation. first network, predictive updating was observed in which the hill of activity jumped directly from initial to remapped target position in a single time-step. In the second network, a gradual shift in the output hill of activation from 30 C105 initial to remapped target position over the duration of the saccade was THE CONTRIBUTION OF THE DORSOLATERAL PREFRONTAL observed, the hill's amplitude being suppressed during this movement. In the CORTEX TO EXECUTIVE FUNCTION third network, the evolution of the output activation combined that of a Ji Hyun Ko 1; Oury Monchi 2; Alain Ptito 1; Antonio P. Strafella 3,4. 1. jumping and a moving hill. Only networks 1) and 3) showed remapping Montreal Neurological Institute, McGill University, Montréal, 2. Functional latencies, as measured by the onset of activity at the updated target location, Neuroimaging Unit, Geriatric’s Institute, University of Montréal, 3. Toronto that spanned the time immediately before and during the saccade, similar to Western Research Institute and Hospital, University of Toronto, 4. PET what has been observed neurophysiologically in the frontal eye fields Imaging Center, Center of Addiction and Mental Health, University of (Umeno and Goldberg 1997). Networks 1) and 3) also showed an absence of Toronto increase of activity at the remapping midpoint during the updating observed in the frontal eye fields (Sommer and Wurtz 2006). Only networks 2) and 3) Introduction: The dorsolateral prefrontal cortex (DL-PFC) is thought to were able to perform the all components of updating across a full 3-D be involved in the monitoring of information held in working memory [1]. saccadic eye movement. Thus, only by using a combination of updating This view has been further supported by previous fMRI studies using the signals were all of the properties observed in updating to date replicated. Wisconsin card sorting task (WCST) [2]. However, functional imaging studies alone cannot assess the exact contribution of a specific brain structure, e.g., the increased DL-PFC activity detected while the subject 29 C104 received feedback during the WCST may not be essential for monitoring, but NEUROANATOMICAL AND COGNITIVE PREDICTORS OF may only be an epiphenomenon. Therefore, to confirm the role of this region, SEXUAL ORIENTATION IN RIGHT-HANDED MEN: AN MRI we investigated the performance of WCST during repetitive transcranial STUDY magnetic stimulation (rTMS) of the DL-PFC. Methods: Ten right-handed Kideckel DM 1*, Kigar DL 2, Scamvougeras A 3, Buck B 4, Stanchev P 5, healthy subjects were stimulated using rTMS over the right DL-PFC and Bronskill M 6, Black S 4 and Witelson SF 2. 1* Institute of Medical Science, vertex (control). The positioning of the coil was chosen according to the Univ. of Toronto; 2 Dept. of Psychiatry & Behavioural Neurosciences, previous fMRI study [2] and using frameless stereotaxy [3]. While the

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subject performed the WCST or the control task, rTMS was given to the 32 C107 subject’s right DL-PFC or vertex at three different timing; (a) at the INFLUENCE OF THE INTRASPECIES RELATIONS beginning of feedback, (b) at the beginning of matching or (c) every 6 sec RESTORATION ON THE BEHAVIOR AND COGNITION during the task (desynchronized stimulation). In each train of stimuli, 20Hz- PROCESSES OF THE RATS rTMS was delivered for the duration of 250 msec in 110% of resting motor * I. Labadze, T. Domianidze, T. Matitaishvili, M. Khananashvili. threshold. The interval between each train depended on the subjects’ reaction time, i.e., roughly about 4 to 6 sec. Paired t-tests were completed in order to Long-lasting deprivation of the social contacts in the early ontogenesis assess potential differences in the reaction time and the number of errors with results in stable disorders of the emotional sphere and behavior. Any stable rTMS in the DL-PFC versus the vertex. Results and Discussion: Reaction form of the inadequate behavior is representation of a pathology, because time was significantly longer for DL-PFC stimulation than vertex stimulation manifests breaching of the relations between organism and its milieu. The (control) when rTMS was given during feedback phase but not during purpose of present stude was to determine, whether is it possible to eliminate matching or when administering desynchronized stimulation. There was no deprivation-induced disorders following restoration of the normal significant difference observed between DL-PFC and vertex stimulation intraspecies connections. Behavior of rats’ were investigated in the following during the control task that does not require active monitoring of working groups: the rats, were isolated since 14th day (I group) and the 30th day (II memory. These findings demonstrated that the DL-PFC is essentially group) of development. Following the two months of isolation these rats implicated in the monitoring of information held in working memory rather were ‘re-socialized’, i.e. each isolated rat was placed into normal social than in the set-shifting process. This is in agreement with the previous fMRI milieu. During investigation of the rats’ behavior following their re- study that showed increased DL-PFC activity while the subjects received socialization, alterations were found in those animals only, which were feedback during the WCST [2]. [1] Petrides M, (2000) Exp Brain Res.; [2] isolated since 30 days of age. when testing in ‘proconflict’ situation number Monchi et al.,(2001) J. Neurosci.; [3] Paus et al.,(1997) J. Neurosci.; Support of the punished drinking acts was significantly higher than in the intact Contributed By: CIHR, FRSQ and REPRIC animals of the same group. After 10-days stressing of the ‘re-socialized’ rats testing the active avoidance response it was found that an index of the correct responses was 90%, whereas before the ‘re-socialization’, the active 31 C106 avoidance responses were completely deteriorated and the new training was EFFECTS OF REPEATED YOHIMBINE ON THE EXTINCTION required for their acquisition anew. Considering this observation, we suggest AND REINSTATEMENT OF COCAINE SEEKING that the state, which develops after ‘re-socialization’ in the rats isolated since *Kupferschmidt, DA, Tribe, E., Erb, S.. Department of Psychology, one month of age, must be attributed to normalized emotional status in these University of Toronto animals. Therefore, has been determined significance of specific periods of the postnatal development. In our experiments, long-lasting isolation (two It is well established that acute exposure to some environmental and months) at early stage (at 14th day) of the postnatal development elicits the pharmacological stressors reliably reinstates drug seeking in rats following stable alterations in the emotional sphere, learning and memory processes, in prolonged extinction training and drug-free periods. To date, however, little the mechanisms of adaptation to stressogenic environment. Following has been done to explore the effects of repeated stress exposure on the recovery of the social contacts anew, the above disorders are irreversible. extinction of drug taking or on subsequent stress-induced reinstatement of Meanwhile, when the rats are isolated since 30 days of age ‘re-socialization’ drug seeking. Because stress typically recurs, investigation of the effects of is capable of partial recovery of the normal level of the behavior and repeated stress on drug seeking is warranted. The present study was designed cognition processes. to determine whether repeated exposure to stress during extinction affects extinction learning and subsequent reinstatement of drug seeking, and whether these effects are modulated by the context in which the stressor is 33 C108 experienced. Rats were trained to self-administer cocaine for 8-10 days. INCREASES IN UNREINFORCED RESPONDING DURING Subsequently, they were given five consecutive days of multiple extinction LIMITED ACCESS TO INTRAVENOUS SELF-ADMINISTRATION sessions; prior to the first extinction session each day, animals were OF HEROIN pretreated with the pharmacological stressor, yohimbine (YOH; 1.25 mg/kg, *Erin Cummins and Francesco Leri. University of Guelph i.p.), or its vehicle (VEH). One hour after being returned to the home cage (HC), animals were given a second injection of the alternate substance, i.e, We have conducted a series of experiments aimed at exploring a VEH or YOH. Thus, for one group of animals, YOH was associated with phenomenon observed in rats self-administering heroin on a continuous extinction learning and the self-administration context, and for the other schedule of reinforcement. That is, during the acquisition phase of heroin group of animals it was not. An additional group of animals was given VEH self-administration, the number of unreinforced lever presses show at both times. After this period of extinction training, animals were left consistent and progressive increases that remain high during maintenance. undisturbed in the HC for nine days. Subsequently, they were given five This is interesting because operant training should result in a decrease, not an additional days of extinction, in the absence of any YOH treatment, followed increase, in lever presses that do not produce additional drug-infusions. Our by a test for the reinstatement of cocaine seeking induced by a YOH studies indicate that this increase is neither related to a tendency to simply challenge. (1.25 mg/kg, i.p.) In the first extinction phase, animals given YOH emit more operant responding with training, nor to excessive responding to before the daily extinction sessions exhibited increased resistance to the cue light present during heroin infusions. Rather, our experiments extinction. Following the second extinction phase (no YOH pre-treatment), suggest that increases in unreinforced responding reflect a progressive these same animals showed a marked attenuation in the reinstatement of enhancement in the animal’s motivation to seek heroin, possibly as a result cocaine seeking induced by a YOH challenge. The results demonstrate that of a change in drive to self-administer the drug. In fact, we have found that repeated exposure to YOH during extinction training induces context- the effects of heroin on locomotion, as well as responding for heroin on a dependent resistance to extinction and attenuation of YOH-induced progressive ratio schedule, both show progressive increases during the reinstatement of cocaine seeking. This research has implications for acquisition of heroin self-administration. In addition, levels of unreinfoced understanding how repeated stress exposure can modulate extinction learning responding in sucrose-trained rats is directly modulated by levels of food- and affect subsequent reinstatement of drug seeking. deprivation and, in heroin-trained rats, an injection of heroin (3 mg/kg) administered prior to a self-administration session decreases unreinforced responding. Supported by NSERC, CFI and OIT.

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34 C109 36 C111 DIFFERENCES BETWEEN ADOLESCENT AND ADULT FEMALE CHRONIC SOCIAL STRESS IN ADOLESCENCE DECREASES AND MALE RATS IN AMPHETAMINE-INDUCED LOCOMOTOR ANXIETY-LIKE BEHAVIOUR, OR INCREASES RISK-TAKING ACTIVITY AND CONDITIONED PLACE PREFERENCE BEHAVIOUR, IN THE ELEVATED-PLUS MAZE IN FEMALES, IZ Mathews & CM McCormick*. Department of Psychology, Brock WHICH LASTS INTO ADULTHOOD University, St. Catharines *Canada Research Chair in Behavioural C Smith, IZ Mathews, & CM McCormick. Department of Psychology and Neuroscience, Professor, Centre for Neuroscience and Department of Centre for Neuroscience, Brock University, St Catharines Psychology, Brock University We have reported previously that chronic social stress (SS) in In rodent models, there are differences between adolescents and adults in adolescence leads to lasting increases in behavioural responses to response to abused drugs that parallel developmental differences in people, psychostimulants in females, but perhaps not males (McCormick et al., 2004, with adolescents typically less vulnerable to aversive effects and more 2005; McCormick & Ibrahim, 2007). Nevertheless, the effects of SS on sensitive to their reward value compared to adults (Leslie et al., 2004). neuroendocrine function in adolescence may be greater in males, which However, most of the preclinical research has focused on prepubescence or showed increased stress-induced CRH mRNA expression in the central early adolescence. We investigated whether female and male rats in late nucleus of the amygdala compared to controls (McCormick et al., 2007). adolescence differ from adults in locomotor and reward responses to Thus, the effects of SS in adolescence in males may manifest for other amphetamine. Reward was assessed using a non-biased conditioned place behavioural endpoints. Here we investigated whether SS in adolescence (16 preference (CPP) test, in which the animal is trained to associate one tactile days of daily 1 h isolation and daily change of cage partner, days 30 to days cue with the drug and another with saline, and is then allowed to choose 45 of age) increased anxiety-like behaviour in the elevated plus maze (EPM; between the cues in a drug-free state. Locomotor activity was recorded anxiety inversely related to open arm exploration) compared to acute stress during the conditioning phase of CPP. Long-Evans rats (n = 120) were tested (1 h of isolation on day 45 only) and no stress (CTL) groups. We also for locomotor activity and conditioned place preference for amphetamine investigated whether SS effects in the EPM would be evident several weeks (0.25, 0.5, or 1.0 mg / kg) during late adolescence (45 - 52 days) or adulthood after SS exposure in adolescence when the rats were adults. When tested on (69 - 76 days). Consistent with studies with prepubescents/early adolescents day 45, SS spent more time on the open arm and had a higher ratio of open (Laviola et al., 1999), late-adolescent females had less locomotor activity to arm entries to total arm entries than CTL (p = 0.005, p = 0.01), and than the first injection of amphetamine compared to adult females irrespective of ACUTE (p = 0.09, p = 0.06). SS also had higher levels of locomotor activity dose, whereas late-adolescent males did not differ from adults. Late- overall in the EPM than CTL (p = 0.007). Estrous Cycle Phase was not a adolescent females also had significant increases in locomotor activity to significant factor in the EPM at day 45. When tested as adults (70 days), SS subsequent injections of amphetamine at all three doses, whereas such spent more time on the open arms than CTL (p = 0.001), but only for estrus, sensitization was only found at the highest dose for adult females and males not diestrus rats, and SS had a lower ratio of open arm entries to total arm of both ages. There was no effect of repeated injection at any dose in late- entries than CTL (p = 0.05), and there was no effect of, or interaction with, adolescent males, although they moved significantly more to amphetamine Cycle Phase (both p > 0.15). For males, only the increase in locomotor than to saline. There were no age differences in CPP, and for all, CPP activity at 70 days of age for SS compared to CTL was significant, although increased with higher doses. In addition, females showed greater CPP during SS males at that age tended to spend less time in the open arms compared to diestrous than during proestrous/estrous phases of the cycle. The sex-specific controls (p = 0.08). Others report increased anxiety after stress exposure in age differences in locomotor responses to amphetamine are not due to adult males with the effect of stress on anxiety sometimes delayed (e.g., Vyas gonadal immaturity (i.e., females are cycling in late adolescence), but may & Chatterjie 2004; Matuszewich et al., 2007). Chronic stress effects on EPM reflect continuing maturation of the neural substrates underlying locomotor behaviour in adult females are inconsistent (e.g., Adamec et al., 2006; Vyas responses to amphetamine, but perhaps not those more relevant for reward. et al., 2005; Renard et al. 2005) perhaps due to estrus-related variation (Mora et al., 1996; Marcodes et al., 2001). The lasting differences in behaviour in the EPM after SS in adolescence in females observed here may reflect 35 C110 increased risk-taking (Macri et al., 2002). RESPONSES TO A REFLECTION OF DOMINANT AND SUBORDINATE CRAYFISH DIVERGE WITH TIME OF PAIRING Holly Y. May* and A. Joffre Mercier. Dept. of Biological Sciences, Brock 37 C112 University NEURAL CORRELATES OF EXPECTED VALUE IN THE SUPERIOR COLLICULUS Reflection has been shown to modify several aspects of crayfish David M. Milstein*, Michael C. Dorris. Center for Neuroscience Studies and behaviour, but only in socialized crayfish. Socialization of crayfish leads to Department of Physiology, Queen's University a stable dominance hierarchy and pairing results in one dominant and one subordinate crayfish per pair. Dominant crayfish paired for 2 weeks spend The expected value of an event is an important variable in the decision more time in a reflective environment than in a non-reflective environment, making process because choosing the option with the highest expected value but subordinate crayfish exhibit no preference. Specific behaviours, such as maximizes the chooser’s intake of reward over time. Expected value is turning toward reflective corners and crossing toward reflective walls are computed by multiplying the probability of reward by the magnitude of enhanced in dominant crayfish and are not enhanced in subordinate crayfish. reward. Whereas the probability and magnitude of reward have previously The present study sought to determine how these responses develop with been shown to influence the production of saccadic eye movements, we time of social pairing. Crayfish housed in a community tank and pairs housed hypothesized that expected value would have a greater impact on saccade together for 30 min. and 3 days were observed in an aquarium with mirrors generation than either of these variables alone. Specifically, we measured on one half of the tank and a non-reflective plastic on the other side. Pairing how expected value influenced saccadic reaction times while recording the crayfish for 30 minutes enhanced most behaviour in response to reflection in preparatory activity of neurons within the primate superior colliculus. We both dominant and subordinate crayfish. After 3 days of socialization recorded neurons in the superior colliculus of non-human primate subjects dominant crayfish continued to prefer reflection, while subordinate crayfish while they performed a simple saccadic task. This task required subjects to appeared to avoid reflection. Thus, responses of dominant and subordinate look to a visual target that could be presented either to the left or right of a crayfish to mirrors diverge with time of pairing. Research supported by central fixation point. There was a short period with no visible stimuli NSERC. between fixation offset and target onset to allow subjects time to prepare a

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saccadic response. Across blocks of trials, the probability and magnitude of appeared once the stimulus had been removed, whereas in phase 2, response reward associated with the left and right targets varied. We found that as windows appeared concurrently with the stimulus. The experiment was expected value of a saccadic target being presented at a location increased, designed so that once criterion level was reached in phase 2, animals would SRTs decreased. We investigated how both preparatory activity in advance of move to Phase 3 (the experimental phase). In this phase, five experimental target presentation and activity time-locked to the presentation of the visual probes were randomly incorporated within every 20 Phase 2 trials. Phase 3 stimulus was affected by manipulations of expected value. We found that consisted of a total of 168 probe trials consisting of eight orientations of the both forms of neuronal activity were influenced by the expected value letter probes, three background orientations, and seven repetitions. After an associated with the potential saccadic responses. Moreover, these neuronal average of 470 trials, none of the animals reached criterion level in phase 1 signals were negatively correlated with the time to initiate a saccade to these and were consequently not able to move to phases 2 and 3. Because of this, targets. Our findings demonstrate that expected value is a decision variable we attempted a second experiment with human participants. In Experiment whose importance is not limited to higher order decision making but is also 2, we investigated the effectiveness of the OCHART with a nonsense figure a critical determinant in preparing simple motor acts such as saccadic eye ‘ ’. Observers were trained to identify the figure as ‘Glib’ when orientated at movements. 0 degrees and ‘Glob’ when orientated at 180 degrees. Ten observers participated and a within-subject design was used. The influence of the background on the PU, using the nonsense figure and the p/d letter probe, 38 C113 was then measured. The two tasks resulted in a similar psychometric function ELECTRICAL STIMULATION OF THE PRIMATE FRONTAL and showed a large effect of the visual background on the PU. However, CORTEX REVEALS EYE-CENTERED AND HEAD-CENTERED analysis of the variances of the estimates of the PU indicate that the REFERENCE FRAMES FOR GAZE COMMANDS observers’ judgment in the p/d trials were less reliable. These results appear J.A. Monteon1,2, J.C. Martinez-Trujillo3, Hongying Wang1,2, J.D. to suggest that measuring the PU using the nonsense figure ‘ ’ is at least as Crawford1,2., 1Centre for Vision Research, York University, Toronto, effective as using the letter probes ‘p’ and ‘d.’ Furthermore, because the ‘p’ 2Department of Biology, York University, Toronto, 3Department of and ‘d’ letter probe of the OCHART are nonsense figures for orangutans, it Physiology, McGill University, Montreal is evident based on experiment 2 that testing the animals with the OCHART may be an appropriate method for measuring the PU, given sufficient training Electrical microstimulation of gaze control structures as the superior on the discrimination task. colliculus (SC) produces gaze shifts defined in an eye-centered reference frame (Klier et al. 2001). In contrast, the supplementary eye fields (SEF) appear to encode gaze commands in multiple reference frames (Martinez- 40 C115 Trujillo et al. 2004; Park et al. 2006). Previous single-unit recording THE ROLE OF THE PREFRONTAL CORTEX IN EXTINCTION experiments in head-restrained monkeys (Russo and Bruce 1996) suggest AND REACQUISITION OF HEROIN SEEKING BEHAVIOUR IN that the frontal eye field (FEF) encodes the location of visual targets in an THE RAT eye-centered reference frame. However, there is reason to suspect that the Ovari, J. & Leri, F., University of Guelph input code (revealed by unit recording) and the output code (probably revealed by stimulation) should not always employ the same reference frame This study looked at the extinction and reacquisition of heroin-seeking (Smith and Crawford 2005). Currently it is not known if electrical behaviour in conditioned place preference. The purpose of the study was stimulation of the FEF in head-free animals produces gaze shifts toward an twofold: firstly, to investigate whether the medial prefrontal cortex (mPFC) eye, head, or space-fixed goal. We implanted two macaques with recording is necessary for the formation of reacquisition memory; and secondly, chambers over the FEF and search coils to measure eye and head rotations. whether it is necessary for the expression of extinction and reconditioning Stimulation trains were delivered at 80 µA, 300 Hz, 200 ms, with gaze memory. Bilateral cannulae were surgically implanted into the ventromedial oriented at a variety of positions. Gaze shifts were evoked from 114 FEF sites prefrontal cortex. Using the conditioned place preference task, animals in two monkeys (M1 n= 70, M2 n=44). Evoked gaze trajectories were underwent habituation, conditioning (0.3mg/kg), and extinction. Following mathematically rotated trajectories into three coordinate systems (eye/ extinction, rats were reconditioned with saline (equivalent to an additional head/space). Then we examined gaze convergence in each of these frames. day of extinction), or heroin (1.0mg/kg). Group one received intra-cranial The distribution of gaze end-points had the lowest amount of convergence to infusions of either vehicle or GABAA/B agonists (muscimol and baclofen, a common point when plotted in gaze coordinates (M1 = 4639.82°2, M2 = 0.03 and 0.3 nmol, respectively/0.5µl/side over 2 min) twenty minutes 2485.60°2). In contrast, gaze end-points had greater convergence when following the reconditioning session. The day after reconditioning, Group plotted in head (M1 =1277.95°2, M2 = 423.23°2) or eye (M1 = 423.2°2, M2 two received vehicle or muscimol/baclofen twenty minutes prior to the = 170.21°2) coordinates. This suggest that the FEF stimulation output is second, drug-free CPP test. Post-reconditioning infusions of characterized by an intermediate trend between an eye-centered reference muscimol/baclofen did not disrupt the subsequent re-emergence of a place frame as observed in the SC (Klier et al. 2001) and a multiple reference frame preference, while pre-testing infusions had no effect on the expression of code used in the SEF (Martinez-Trujillo et al. 2004). extinction memory or on drug-seeking in heroin reconditioned rats. Supported by NSERC.

39 C114 MEASURING THE PERCEPTUAL UPRIGHT IN GREAT APES: 41 C116 EFFECTIVENESS OF THE OCHART THE FACILITATIVE EFFECTS OF D-CYCOSERINE ON Jean-Francois D. Nankoo*, Laurence R. Harris, Suzanne E. MacDonald. EXTINCTION OF A COCAINE-INDUCED CONDITIONED PLACE Department of Psychology, York University PREFERENCE CAN BE LONG LASTING AND RESISTANT TO REINSTATEMENT: EFFECTS OF EXTINCTION VARIABLES We investigated the role of visual background on the Perceptual Upright G. Paolone*, A. Benatar, J. Stewart. Center for Studies in Behavior (PU) in four Sumatran orangutans (Pongo abelii), housed at the Toronto Zoo, Neurobiology, Concordia University, Montreal using the Oriented CHAracter Recognition Technique (OCHART) (Dyde et al., 2004 Exp Brain Res. 173: 612). Prior to experimental sessions, two Extinction of conditioned responses based on aversive and appetitive training phases were administered for the animals to learn the discrimination unconditioned stimuli (US) is used as a therapeutic measure to reduce fears between the character ‘p’ and ‘d’, which were superimposed on a circular or cravings. For example the reduction of conditioned fear involves the polarized picture. In phase 1 of the training protocol, response windows repeated presentation of conditioned fear stimulus (CS) in the absence of the

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US (an extinction procedure). Similarly, the reduction of conditioned plays a role in guiding late (adolescent) developmental processes related to cravings or appetites can be brought about by repeated presentation of the stress response circuitry, resulting in altered adult physiology and behaviour. conditioned appetitive stimulus (CS) in the absence of a US, such as food or injection of a drug of abuse. Recently it was shown in a series of experiments that extinction of conditioned fear responses can be facilitated by injection of 43 C118 the partial NMDA glutamatergic receptor agonist, D-cycloserine (D-4- EFFECT OF MICROSTIMULATION OF MACAQUE ANTERIOR amino-3-isoxazolidone, DCS), a compound that acts at the strychnine- CINGULATE CORTEX ON REACTION TIMES AND insensitive glycine-recognition site of the NMDA receptor complex. We PERFORMANCE OF PRO- AND ANTI-SACCADES found previously that DCS significantly accelerates extinction of cocaine- J. Phillips, K. Johnston, S. Everling. Graduate Program in Neuroscience, induced conditioned place preference (CPP) when rats are given systemic or University of Western Ontario, London, Robarts Research Institute, London basolateral amygdala injections immediately, but not 4 hours, after each Department of Physiology and Pharmacology, University of Western extinction trial. Here we report that when extinction trials are spaced, the Ontario, London effect of DCS can be long-lasting and resistant to cocaine-induced reinstatement. Groups of rats were trained on a CPP where they were given The dorsal anterior cingulate cortex (ACC), Brodmann’s area 24c, is a 4 cocaine (10 mg/kg, i.p.) and 4 saline pairings with one of two brain region that has been implicated in decision making, error detection, compartments of a 3-compartment test box. Following a CPP test, extinction task-switching and other aspects of executive control. The anti-saccade task trials were given on days 4, 7, 10, and 24 and were followed immediately by has become a popular tool in the investigation of the voluntary control of DCS (15 mg/kg, i.p.) or saline. A final extinction test was given on D38 behaviour. This task requires the suppression of the automatic tendency to followed by a reinstatement test 5 days later in which rats were given 5 look towards a flashed stimulus, and a vector-remapping of a voluntary mg/kg cocaine before the test. When extinction trials were given at 3-day saccade in the opposite direction to its mirror location in the visual field. Our intervals there was little extinction of the CPP in the saline group. However, laboratory has recently demonstrated that, before peripheral stimulus extinction was greatly facilitated in rats that received DCS after each trial and presentation, neurons in the monkey ACC exhibit task-selectivity when the no reinstatement was seen. In other experiments, we are exploring other monkey prepared to look towards a peripheral stimulus (pro-saccade) parameters of extinction training on the effect of DCS. Support Contributed compared to when they prepared to look away from the stimulus (anti- By: Canadian Institute of Health Research saccade). Here, we have further investigated the ACC’s role in top-down control by administering electrical microstimulation in the ACC of the monkey while it performed alternating blocks of the pro- and anti-saccade 42 C117 tasks. Microstimulation pulse trains were administered (biphasic, 0.3 ms, 100 ADOLESCENCE AS A SENSITIVE PERIOD FOR DEVELOPMENT Hz, 50-80 mA) 200 ms prior to stimulus presentation and persisted for a OF ENDOCRINE AND BEHAVIOURAL STRESS RESPONDING IN duration of 300 ms in total. Microstimulation increased reaction times RATS significantly compared to no stimulation for pro-saccades in both the Lisa Wright, Katherine Muir, and Tara Perrot-Sinal. Psychology leftward and rightward direction (p < 0.0001). An effect of microstimulation Department/Neuroscience Institute, Dalhousie University was also evident for anti-saccade reaction times, where contralateral reaction times were decreased compared to no stimulation and ipsilateral reaction Dynamic processes underlie gene-environment interactions during times were increased (p = 0.0014 for contralateral, p = 0.0011 for ipsilateral). development, and these have long lasting consequences for the adult Performance as a percentage correct of total trials was also significantly phenotype. Relative to the neonatal period, less work has examined affected by microstimulation for ipsilateral pro-saccades on which development during adolescence, though different components of neural microstimulation impaired performance (p = 0.024), and contralateral anti- systems are sensitive at this time. In particular, programming might occur in saccades, where microstimulation enhanced performance (p = 0.0107). frontal components of stress response circuitry during the adolescent period, since major developmental modifications occur here at this time. We have previously developed an ethologically relevant adolescent stressor paradigm, 44 C119 periadolescent predator odour (PPO) exposure, for use in rats. This ROLE OF THE HUMAN POSTERIOR PARIETAL CORTEX IN manipulation is considered to model a higher risk environmental context. TRANSSACCADIC MEMORY The present series of experiments undertook to examine the temporal Steven L Prime, Michael Vesia, Lauren E. Sergio, J. Douglas Crawford. specificity of effects, through comparison of PPO effects in juveniles with York University, Toronto those in a control group who received stressor exposure in early adulthood. Behavioural assessment involved two open field sessions (OF1 and OF2) and We previously reported that transsaccadic memory has a similar capacity a predator odour stress test (OFPO) administered ~20 days following for storing simple visual features as basic visual memory (Prime & Crawford, juvenile or adult manipulations. Though there were effects of treatment age VSS abstracts, 2006). Here, we tested how many object features and and sex, only a few were specific to cat odour treatment (which was locations could be retained across saccades while applying single-pulse compared with control odour treatment in both age frames). Regardless of transcranial magnetic stimulation (TMS) over the right dorsal posterior treatment age, those who received no prior odour experience groomed more parietal cortex (PPC). Five subjects were presented with a random number of frequently during OF2 (p=0.028), but less frequently during OFPO, relative targets (1, 3, 4, 5, 6, or 8) with different spatial positions and orientations. to those who had received odour priming (p=0.013). Juveniles who received Subjects were instructed to fixate and remember the positions and odour priming spent less time in contact with the odour source during OFPO, orientations of the targets. Then, subjects made a saccade to a different compared with juveniles who had not (p0.001). This pattern was not present random location and were presented with a probe at the same location as one in the adult-treated group. Plasma corticosterone (cort) levels examined of the pre-saccadic targets, but tilted 9 clockwise or counter- during priming revealed a higher normalized cort response in the odour- clockwise. Subjects made a force-choice response to indicate how the primed animals (p=0.002). Normalized cort responses to OFPO were higher probe’s visual feature differed from the original target. In each trial, we in juvenile-exposed relative to adult-exposed animals, regardless of odour randomly delivered a single-pulse at one of seven different time intervals treatment (p=0.01). Testosterone (T) levels were also examined in males, centred around the saccade-go signal (-300ms, -200ms, -100ms, 0ms, and, while odour treatment had no effect on circulating T levels, there were +100ms, +200ms, +300ms). Thereby, allowing us to obtain information of significant correlations between T levels and cort responses to OFPO. These the timing of the contribution of the right PPC during task performance effects support the contention that exposure to species-specific stressors (causal chronometry). Our preliminary data shows that performance was

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disrupted during stimulation of the right PPC, particularly between 100ms to different conditions. In the self-ordered condition, the subject had to select a 300ms after the saccade-go signal. Stimulation at the other time intervals different face on each one of six trials. All six faces were presented on each showed no statistical differences compared to the baseline (no TMS). The trial but at a different location. In the externally triggered condition, during findings suggest that TMS over the right PPC transiently disrupt the putative the first five trials, a different face was cued by the computer and the subject spatial processing involved in transsaccadic memory. was required to select these faces and track them regardless of their location. On the sixth trial, the participant had to select the only face that had not previously been cued. In the recognition condition, one of the six faces was 45 C120 cued, before the first trial. During the six trials that followed the subject was RESPONSES OF MEDIAL PREFRONTAL CORTEX NEURONS TO asked to select the cued face independently of its location. In the control STIMULATION OF THE THALAMUS AND HIPPOCAMPAL condition, the same face was cued throughout the six trials and the subject FORMATION: AN IN VIVO STUDY IN THE CAT was asked to select it. Following an anatomical T1 sequence, four functional Éliane Proulx*, Igor Timofeev. Centre de Recherche Université Laval runs were acquired, each containing 204 frames (TR: 2.5s; 36 slices; voxel Robert-Giffard, Québec size: 3.4x3.4x3.4 mm3). Subjects completed four blocks of the four conditions per run. As predicted, we found significant increased activity of Interactions of the hippocampus and prefrontal cortex are known to be the DLPFC in the self-initiated condition and the externally triggered critical in supporting higher cognitive functions such as learning and condition as opposed to the recognition and control conditions. Furthermore, memory. The hippocampo-prefronto-thalamic network is composed of the we observed a significant increased activity in the right caudate nucleus, but medial prefrontal cortex (mPFC), the reuniens nucleus of the thalamus (RE) not in the DLPFC when we compared the self-initiated condition to the and the hippocampal formation (HF). It has been proposed that the RE may externally triggered condition. The study provides further evidence that the serve as an interface between the mPFC and HF, given that the mPFC does DLPFC is particularly important for the monitoring of information in not reciprocate connections with the HF (Vertes 2006). While the working memory regardless of whether it is internally or externally triggered. hippocampo-cortical pathway of this hippocampo-cortico-thalamic circuit However, unlike the dorsolateral PFC, the caudate nucleus seems particularly has been well characterized, the thalamo-cortical one has not. Here we important when monitoring is self-generated as opposed to externally- describe for the first time mPFC neural responses to RE and HF electrical triggered. stimulation. We have performed in vivo intracellular recordings in the mPFC of ketamine/xylazine anesthetized cats. Out of 28 neurons retained for analysis, 18 were identified as regular-spiking, 2 as intrinsically-bursting and 47 C122 2 as fast-rhythmic-bursting. Eleven out of 20 tested neurons were responsive EFFECT OF AMYGDALA LESIONS ON LITHIUM-INDUCED to RE stimulation, 6 out of 22 to HF stimulation, and 1 out of 16 to both RE CONDITIONED DISGUST AND TASTE AVOIDANCE and HF stimulation. Thalamic stimulation led to a primarily excitatory Shadna A. Rana* and Linda A. Parker. Wilfrid Laurier University*, response of variable latency throughout the dorso-ventral extent of the mPFC University of Guelph with some responses being followed by a period of disfacilitation and a rebound. Antidromic spikes of 2-4 ms were detected approximately 6 mm The effect of amygdala lesions on conditioned disgust and taste below the cortical surface, in what corresponds to the prelimbic area of the avoidance were examined in male Sprague-Dawley rats that received cat. On the other hand, mPFC responses to HF stimulation were not always bilateral NMDA (12.5 mg/ml) lesions of the basolateral amygdala (BLA) or reliable; stimuli delivered at slightly supra-threshold intensities were able to ibotenic acid (10 µg/µl) lesions of the central nucleus of the amygdala (CeA) elicit an initial response from 14% to 100% of the time, suggesting a gating compared to sham-lesioned rats in taste reactivity (TR) and consumption mechanism in the HF – mPFC pathway. Responses usually consisted of an (bottle) tests. Following recovery from surgery, the rats received two initial excitation, with a latency of approximately 10 ms, followed by a silent conditioning trials in which they were intraorally infused with 0.1% period of disfacilation which in turn led to a rebound. The initial excitation saccharin solution (at a rate of 1 ml/min for 5 min) followed by an injection was not, however, consistently paired with a hyperpolarizing event. We of 0.15 M lithium chloride (130 mg/kg; Group Paired) at a volume of 20 conclude that the RE-mPFC network interacts efficiently and that only ml/kg or equivolume physiological saline (Group Unpaired). During the TR limited parts of mPFC receive inputs from both RE and HF. Supported by test, rats were infused with the conditioned stimulus (CS) solution for a NSERC and CIHR. period of 2 min and their orofacial and somatic responses were recorded. During the consumption tests, rats received one-bottle (CS) and two-bottle (CS and water) tests. The amount consumed, over several time periods, was 46 C121 recorded. The results suggest that frequency of total aversive responses (e.g., ROLE OF THE CAUDATE NUCLEUS IN SELF-ORDERED AND gape, chin rub and paw tread) exhibited by BLA- and CeA- lesioned rats, to EXTERNALLY TRIGGERED MONITORING TASKS: AN EVENT- intraoral infusion of a lithium-paired taste, are similar to those of sham- RELATED FMRI STUDY paired rats; that is, conditioned disgust may not be affected by BLA or CeA Provost, JS.*,1 Petrides, M.,2 Guizard, N.,1 Monchi, O.1. 1-Functional lesions. However, only BLA lesioned rats exhibited a conditioned taste Neuroimaging Unit, Centre de Recherche de l’Institut Universitaire de avoidance deficit. The findings support the notion that the BLA (not CeA) Gériatrie de Montréal, & Department of Radiology, Université de Montréal plays a role in conditioned taste avoidance learning and the amygdala is not 2-Montreal Neurological Institute, & Department of Psychology, McGill involved in conditioned disgust. University

It has been suggested that the dorsolateral prefrontal cortex (DLPFC) is 48 C123 involved the monitoring of information [2]. Monchi et al. have proposed that ULTRASONIC VOCALIZATIONS IN RESPONSE TO PALATABLE the caudate nucleus is significantly involved during the planning of self- FOOD CUES ARE REDUCED IN M5 KNOCKOUT MICE generated actions [1]. Here, we attempted to test the hypothesis that the Aliona Rudchenko1, Haoran Wang1, Cindy Chiang1, Jeffrey Burgdorf2, caudate nucleus is required to a greater extent when the monitoring is self- John Yeomans1. 1 Center for Biological Timing and Cognition, Department generated as opposed to externally triggered. Twelve right handed healthy of Psychology, University of Toronto, 2 Falk Center for Molecular subjects (6 males, 18 to 30 years old) were scanned using 3T fMRI while Therapeutics, Northwestern University, Evanston, IL, USA performing the self-initiated and externally triggered monitoring tasks of Petrides [2]. Six faces were presented in two rows of three. There were four Rats produce high frequency ultrasonic vocalizations (USVs) in appetitive situations. High frequency USVs (50kHz) are related to the

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activation of dopaminergic systems. Previous evidence indicates that mice during extinction training, indicating that GABA signalling is required muscarinic receptors in VTA are involved in activation of dopamine neurons, for this process. and in food-related behaviours in rats and mice. The present study investigated whether M5 muscarinic receptors are involved in rewarding aspects of food stimuli in mice. USVs (40-110kHz) were studied in female 50 C125 wild-type and M5 muscarinic receptor gene knockout mice with palatable POST-TRAINING EFFECTS OF THE GINKGO BILOBA LEAF and unpalatable food cues (Moles & d’Amato, 2000). Mouse pairs were EXTRACT, EGB761, ON MEMORY separated for 7 hours, and then one mouse was exposed to 30 min of chow, Elham Satvat* & Paul E. Mallet. Wilfrid Laurier University including either chocolate (palatable) or fennel seeds (unpalatable). Each mouse was then placed in a cage with the other mouse, and social USVs were Ginkgo biloba extracts are widely used for their pro-mnemonic effects. measured for the pair. In the first minute after placing the mice together, One such extract, called EGb761, has repeatedly been shown to improve wild-type mice produced significantly more USVs in response to palatable learning when administered chronically prior to and/or during the learning than unpalatable food cues. The difference declined in the second minute, phase. However, the influence of EGb761 on memory per se, assessed by and disappeared in the third minute. USVs in M5 knockout pairs were not administering the extract during the interval between training, is less clear. In different between palatable and unpalatable food, suggesting that the M5 the present study, we examined the acute and chronic effects of post-training receptor is required for the increase in USVs in response to palatability cues. administration of EGb761 in laboratory rats using a double Y-maze task. When the mice were deprived of food during the separation, M5 knockout Each trial consisted of two components: a spatial discrimination and a mice showed fewer USVs than wild-type mice after exposure to either delayed alternation. The non-mnemonic demands of the two components are palatable or non-palatable food. These data show that M5 receptors play an roughly equivalent; that is, both involve a food-reinforced two-arm important role in mediating USVs in response to rewarding food stimuli. discrimination in a Y-maze. However, in trained animals only the delayed Thank Stephan Steidl for advice and discussion. Supported by CIHR grant to alternation component requires the use of working memory. Accordingly, if JY. a treatment selectively influences performance in the delayed alternation task, we can confidently rule out the treatment’s influence on non-mnemonic factors, such as motivation, motor function, and sensory alteration. In the 49 C124 first experiment, twelve rats received 24 consecutive training trials per day in IMPAIRMENT OF FEAR EXTINCTION IN THE GAD65 KNOCK- the double Y-maze until they reached a training criterion of 21/24 correct OUT MOUSE trials over 3 consecutive days. Rats then were injected with vehicle, 0.75, 7.5, Sangha S*(1), Bergado J(2), Stork O(2), Seidenbecher T(1), Pape HC(1). 41.25, or 75 mg/kg EGb761 (i.p.), 30 min prior to each test session, in a (1) Institut for Physiologie I, Westfaelische Wilhelms-Universitaet Muenster, counterbalanced order using a within-subject design. Delay intervals (0, 15 Muenster, Germany, (2) Institut for Physiologie, Otto-von-Guericke- or 60 sec) were introduced between successive trials (8 trials at each delay), Universitaet, Leipzigerstr. Magdeburg, Germany serving to vary the task’s working memory demands. Rats were re-trained to criterion between drug treatments. Results revealed that acute administration Extinction is demonstrated as a reduction in fear that occurs when stimuli of EGb761 had no significant effect on either the spatial discrimination task, once associated with an aversive event are no longer coupled with that event or the delayed alternation (i.e., working memory) task. In a second and involves new learning and memory formation rather than erasure of the experiment, the same rats were randomly assigned to two groups. One group original memory. Pharmacological studies have implicated GABA in received 21 daily injections of vehicle, while the other group received 21 extinction. GABA production is mediated by the enzyme GAD which exists daily injections of 42.25 mg/kg EGb761 (i.p.). Rats were then tested twice in in 2 isoforms: GAD65 and GAD67. GAD67 maintains basal GABA levels the double Y-maze, once under the influence of the drug and once in a drug- whereas GAD65 is rapidly activated in times of high GABA demand and is free state. Results revealed no difference in performance between groups, essential for regulating responses to environmental signals, such as those under both drugged and drug-free conditions. Taken together, these data encountered during learning. Mice lacking GAD65 (GAD65-/-) display suggest that both acute and chronic post-training administration of EGb761 elevated anxiety levels. Fear and extinction learning were examined in does not enhance memory. GAD65-/- mice and wild-type littermates (GAD65+/+). Fear conditioned GAD65+/+ mice froze more to the tone associated with the foot shock than to the neutral tone, whereas GAD65-/- mice showed high freezing to both 51 D101 tones, indicating stimulus generalization. Extinction training consisted of 6 GLYCINE INHIBITION OF STARTLE MEDIATING NEURONS IN sessions. In GAD65+/+ mice, extinction of fear was apparent in the 4th THE RAT CAUDAL PONTINE RETICULAR FORMATION session and still evident 24hrs later, demonstrating long-term memory for Hans-Ruediger Geis (1,2), *Susanne Schmid (1,3). (1)Tierphysiologie, extinction training. Extinction of fear was less pronounced in GAD65-/- Universität Tübingen, Germany; (2)Dept of Neuroscience, Erasmus MC mice, not being readily apparent until the final session with no long-term University of Rotterdam, Netherlands; (3) Dept. of Psychology, University of retention. Field potential recordings from the lateral amygdala (LA), CA1 Toronto and prefrontal cortex (PFC) were simultaneously obtained in freely behaving mice during extinction training. Before extinction training, GAD65+/+ and - The mammalian startle response is an excellent model for studying /- mice exhibited high theta phase correlation levels between all 3 brain areas, cellular and molecular mechanisms underlying behaviour and learning. The with the LA-CA1 correlation being the highest, consistent with high fear startle response is strongly controlled by glycine inhibition. An impairment behaviour. After extinction training, the LA-CA1 correlation decreased in of glycinergic inhibition is responsible for the neurological disorder GAD65+/+ and -/- mice. Theta phase correlation levels remained high Hyperekplexia. Glycine inhibits startle on the level of the spinal cord, between the PFC-CA1 and LA-PFC after extinction training in GAD65+/+ however, there is controversial evidence for additional glycine inhibition on mice but decreased in the GAD65-/- mice. Thus, in GAD65+/+ mice the the level of the brainstem, namely in the caudal pontine reticular nucleus correlation levels were uneven across the 3 brain areas, with LA-CA1 being (PnC). Giant neurons in the PnC play a crucial role in mediating the the lowest, consistent with low fear behaviour. In GAD65-/- mice, the LA- mammalian startle response. They receive input from different sensory CA1 correlation remained the highest of the 3 even though its value had pathways and project directly to facial, cranial and spinal motoneurons. decreased after extinction training, consistent with persistence of fear Furthermore, they integrate modulatory input from different brain regions behaviour. Taken together, the development of high theta phase correlative that either enhance or inhibit startle responses. In the present study we activity between the PFC-CA1 and LA-PFC does not occur in GAD65-/- performed patch-clamp recordings of PnC giant neurons in rat brain slices

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and we tested the effect of glycine and the glycine antagonist strychnine on Humans can substantially improve the search for a particular visual active and passive cell parameters as well as on synaptic signals evoked by object among several others by guiding their visual attention to a given stimulation of auditory and trigeminal afferent fibres within the startle feature of that object. We have previously shown how the visual behavior of pathway. While strychnine had no effect on PnC giant neurons, the nonhuman primates is also influenced by scene composition and how their application of glycine strongly inhibited PnC neuron activity. The membrane visual search strategies are guided by stimulus salience (Shen and Paré, resistance dropped from 101 ±16 MΩ to 30 ±4 MΩ (F(3,31) 2006). In the current study, we investigated the neural mechanisms 06.68; p=0.0011) , leading to an altered resting potential, decrease in underlying these contextual effects by recording 39 visuo-motor neurons spontaneous activity and to significant inhibition of both evoked spiking from the intermediate layers of superior colliculus (SC) while three monkeys activity and evoked synaptic currents (EPSCs; F(3,31)=7,72; p=0.0005) performed a visual conjunction (color+form) search task. The search target while the paired pulse ratio of EPSCs was not altered. All effects could be appeared pseudorandomly with 11 distractors in a concentric array. As color reversed by additional application of 10 µM strychnine. Our results show that was the most discriminable feature in this task, the number of distractors exogenous glycine activates functional glycine receptors expressed on PnC sharing the color of the target was varied between three distractor ratios (2 giant neurons, and that this is able to mediate a powerful inhibition of the same-color: 9 different-color; 6:5; and 9:2). As previously reported, startle mediating neurons over a wide range of glycine concentrations. monkeys’ search strategies changed flexibly with the display type: saccades were more likely to land on distractors sharing the target color when there were few of them in the display (i.e., when they were salient) and monkeys 52 D102 were less likely to choose those distractors when they were numerous. The PARIETAL LOBE ANATOMY AND VISUOSPATIAL ABILITY IN A initial (first 25 ms) neuronal response to the target or distractors was invariant GIFTED GEOMETRICIAN: CASE STUDY OF HAROLD S.M. with distractor ratio. Over time, however, the ideal observer discriminated COXETER the target from distractors. The discrimination of the target from a salient *Scott CJM(1), Kigar DL(2), Black SE(3), Witelson SF(2). (1)M.Sc. Student, distractor was more difficult and occurred later than the discrimination of the Medical Sciences, McMaster Univ.; (2)Dept. of Psychiatry & Behavioural target from less salient distractors across all display types, suggesting that Neurosciences, McMaster Univ.; (3)Sunnybrook Health Sciences Centre, neurons are functionally feature selective. At the time when neurons Univ. of Toronto generally discriminated the target from distractors, neuronal activity The definition and measurement of intelligence and the neurobiological associated with each distractor type (i.e., functional feature selectivity) was basis of its variation have been the subject of much study. Intellectual ability proportional to the monkeys’ probability of selecting that stimulus for a is related to cerebral anatomy in complicated relationships (Witelson, Beresh saccade. These results extend previous behavioral distractor-ratio studies by & Kigar, 2006; Colom et al., 2006). One component of general intelligence showing how superior colliculus activity reflects the flexible guidance of is visuospatial ability which is largely mediated by the superior parietal visual attention in different contexts. lobules (SPL). The SPL of both hemispheres are activated in tasks such as mental rotation of 3-D objects and the generation and manipulation of visual imagery. The purpose of this study was to examine brain structure in an 55 D105 individual case of visuospatial excellence, compared to a group of age- DOPAMINERGIC MODULATION OF RISKY-DECISION MAKING matched normal controls. The case subject, Harold Coxeter (HC) was a Jennifer R. St. Onge and Stan B. Floresco. Department of Psychology, world-acknowledged gifted geometrician. He volunteered to be part of our University of British Columbia,Vancouver research program at the age of 92, upon learning of our study of the brain of Albert Einstein. Intelligence testing was performed on HC using the Alterations in decision making about risks and rewards is associated with Wechsler Adult Intelligence Scale and Coxeter scored in the 97th, 93rd, and a variety of clinical disorders, including substance abuse, ADHD, and 97th percentiles for Verbal, Performance and Full Scale IQs respectively. Parkinson’s disease. Animal studies suggest that the mesolimbic dopamine Structural MRI's were acquired at Sunnybrook Health Sciences Centre. Our (DA) system is involved in certain types of decision making, but the role of hypothesis was that the anatomy of his parietal lobes would be different from DA in risky-decision making has yet to be fully explored. Lesions to DA normals based on our previous findings on Albert Einstein. The MRI scans terminal regions (e.g. ventral striatum, orbitofrontal cortex) alter patterns of of twelve cognitively normal control subjects were obtained from risky-decision making when rats have to choose between small, certain Sunnybrook (mean age 81.1 years). All, including HC, had T1-weighted 3-D rewards and large rewards delivered on a probabilistic schedule. We magnetic resonance imaging scans acquired on a General Electric Signa 1.5 examined the role of DA and its specific receptor subtypes in risky-decision Tesla scanner using standard parameters. All MRIs were processed using the making. We used an automated task conducted in an operant chamber in program Semi-Automated Brain Region Extraction (Dade et al., 2004), combination with systemic administration of the DA releaser amphetamine, which parcellates the brain into 26 volumes of interest, using a set of as well as selective DA agonists and antagonists. Rats were initially trained manually defined landmarks and coordinates. We found that HC’s left SPL to press retractable levers to receive sugar pellet reward. During the risky- was 4.7 standard deviations larger than the control group. There was a decision making task, a single press on one lever (small/certain) immediately tendency for the right SPL to be greater (SD = 1.6). No differences were delivered one pellet, whereas a press on the other lever (large/risky) delivered observed in other regions. We suggest that his increased parietal region may four pellets but with the probability of receiving reward decreasing across the be part of a neuroanatomical substrate that allowed for extraordinary four trial blocks (100%, 50%, 25%, 12.5%). Once choice behavior stabilized, visuospatial ability. The finding of atypical anatomy and increased volume in separate groups of rats received injections of saline or the following the parietal region in two cases with exceptional visuospatial ability supports dopaminergic drugs: amphetamine, SCH23390 (D1 antagonist), eticlopride the notion of an association between ability in a specific cognitive domain (D2 antagonist), L745,870 (D4 antagonist), SKF81297 (D1 agonist), and anatomy of the relevant cortical regions. The roles of heredity and PD168,077 (D4 agonist). Administration of amphetamine dose dependently experience in this association remain to be addressed. increased preference for the large/risky lever at 3 doses tested (0.25, 0.5, 1.0 mg/kg). Blockade of D1 or D2 receptors with SCH23390 (0.005 mg/kg) or eticlopride (0.01 mg/kg) respectively, decreased preference for the 53 D103 large/risky lever. Furthermore, co-administration of these drugs blocked the THE NEURAL REPRESENTATION OF STIMULUS SALIENCE amphetamine-induced increase in risky choice. Blockade of D4 receptors PREDICTS BEHAVIORAL CHOICE WHEN SELECTING VISUAL also caused a moderate decrease in risky choice, but the effects were not as OBJECTS prominent as those observed with D1 and D2 antagonists. Direct stimulation Shen, Kelly* and Paré, Martin. Centre for Neuroscience Studies, Department of D1 receptors with SKF81297 increased choice of the large/risky lever at of Physiology, Queen's University, Canada one dose (0.3 mg/kg) but exerted a biphasic effect at a higher dose (1.0

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mg/kg), where rats were risk averse on the 50% probability block but risk 58 D108 prone on the 25% probability block. PD168,077 (1.0 mg/kg) also increased SACCADE PREPARATORY ACTIVITY WITHIN THE PRIMATE risky choice, but again, the effects were not as prominent as with the D1 SUPERIOR COLLICULUS IS PREDICTIVE OF UPCOMING receptor agonist. The results of this study suggest that DA activity contributes CHOICES DURING A STRATEGIC GAME. to risky-decision making. D1 and D2 receptors appear to be strongly Dhushan Thevarajah*, Michael Dorris, Areh Mikulic. Department of mediating this behaviour, with D4 receptors playing a less important role. Physiology and Centre for Neuroscience Studies, Queen’s University, These results clarify the specific role of DA receptor subtypes in risky- Kingston, ON decision making, which may have implications for clinical disorders that are associated with alterations in this form of executive functioning. Previous research suggests that during perceptual-based decisions, incoming sensory evidence leads to an accumulation of neural activity in brain regions involved in generating the appropriate motor response. Here we 56 D106 investigated whether motor preparatory activity accumulates in a similar INDIVIDUAL DIFFERENCES IN VULNERABILITY TO STRESS- manner during strategic decision-making in which there is no immediate AND COCAINE-INDUCED RELAPSE TO COCAINE SEEKING IN sensory information to indicate the correct choice. Monkeys played an RATS oculomotor version of the mixed-strategy game ‘odds-evens’ while the Martin Sticht, AnneMarie Levy, Craig Allen, Mark Tucci & Francesco Leri. activity of single neurons with saccade preparatory activity was recorded Department of Psychology, University of Guelph from intermediate/deep layers of the superior colliculus (SC). Each trial began with fixation of a central visual stimulus which was extinguished for The aim of the present study was to investigate individual differences in a 600 ms warning period before two targets were presented; one in the center relapse vulnerability as assessed by differences in the reinstatement of and the other opposite the neuron’s response field. If both monkey and the operant responding for a cocaine-conditioned stimulus. Thus, rats (n = 98) computer opponent chose the same target (i.e., ‘evens’), the monkey received received three sessions of Pavlovian conditioning whereby a light-buzzer a liquid reward; otherwise (i.e., ‘odds’) the computer opponent received a stimulus was paired with intravenous infusions of cocaine (0.5 mg/kg/inf; virtual liquid reward. Statistical analyses showed that monkeys approached one 3h session/day). Following withdrawal (5 days), operant responding for the optimal strategy of choosing each target stochastically and in equal the light-buzzer stimulus was assessed on 3 test sessions (3hr/day) in proportions. This behavioral equilibrium suggests that the two responses extinction conditions, and on two counterbalanced tests of reinstatement were, on average, of equal desirability. Preparatory activity within the SC induced by foot shock stress and by cocaine primes (15 mg/kg i.p.). Despite became increasingly selective of whether the target in the response field or identical regimen of cocaine exposure, 8% of the subjects showed selective opposite the response field would be chosen as the saccadic target. Despite reinstatement to stress, 14% selective to cocaine, 36% responded to both an overall equality in desirability for the two responses, the timing of the stress and cocaine, and 42% showed no reinstatement. These data in rats differential accumulation of saccade preparatory activity leads us to conclude suggest that individual differences in vulnerability to relapse can be that monkeys commit to one of the responses in advance of target independent from intensity of previous drug exposure. Supported by CIHR, presentation. CFI and OIT

59 D109 57 D107 A MUTATION IN CREB DISRUPTS LONG-TERM MEMORY FOR CAFFEINE-CONDITIONED PLACE AVERSIONS ARE SWITCHED HABITUATION AND BLOCKS MEMORY ASSOCIATED TO CONDITIONED PLACE PREFERENCES BY DOPAMINE CHANGES IN GLUTAMATE RECEPTOR SUBUNIT EXPRESSION RECEPTOR BLOCKADE Tiffany A. Timbers*, and Catharine H. Rankin. Department of Psychology Sturgess, J.E.(1), Ting-A-Kee, R.A.(2), Podbielski, D.(3), van der Kooy, and the Brain Research Centre, University of British Columbia D(3).. 1 Department of Medical Biophysics, 2 Institute of Medical Science, 3 Department of Medical Genetics and Microbiology Through behavioural mutant analysis we have shown that the transcription factor CREB (cAMP response element binding protein) is Despite caffeine’s status as the most widely consumed psychoactive necessary for long-term, but not short-term memory of mechanosensory substance in the world, the precise neurobiological mechanisms underlying habituation in the nematode, Caenorhabditis elegans. We tested crh-1 its motivational effects remain unclear. The mesolimbic dopaminergic (homologous to the mammalian CREB protein) mutant worms, which have a system is important for both the rewarding and aversive motivational aspects 979 DNA base pair deletion that eliminates 38 amino acids of the bZIP DNA of many natural and drug rewards. For this reason, we investigated the role binding domain (Kimura et al., 2002), for short-term and long-term memory of dopamine in caffeine motivation using a fully counterbalanced deficits. crh-1 mutant worms showed no significant differences from wild- conditioned place preference paradigm. Systemic (i.p.) administration of type worms when tested for short-term habituation, but when tested for long- caffeine in wild type C57Bl/6 mice produced dose-dependent conditioned term memory of habituation training, crh-1 mutant worms showed no place aversions at 10, 30 and 100 mg/kg. However, pre-treatment with the evidence of long-term memory 24 hours later. Through confocal imaging of broad-spectrum dopamine receptor antagonist alpha-flupenthixol (0.8 mg/kg, GLR-1 (homologous to non-NMDA type glutamate receptor subunit 1) i.p.), under conditions where alpha-flupenthixol produces no motivational subunits tagged with GFP our lab has shown that consolidation of memory effects of its own, not only abolished these caffeine conditioned place for habituation in C. elegans is associated with a decrease in the average area aversions but resulted in robust caffeine conditioned place preferences. In of GLR-1 synaptic clusters 24 hours after long-term memory training. This addition, the conditioned place aversion produced by 10 mg/kg caffeine was is not observed in naïve worms (Rose et al., 2003). Here we report that crh- blocked, and a conditioned place preference was revealed, by pretreatment 1 mutant worms expressing the GLR-1::GFP transgene do not show a with both D1- and D2-receptor-selective antagonists, and this effect was decrease in the average area of GLR-1 synaptic clusters 24 hours after long- replicable in D1- and D2-receptor knockout animals. These results suggest term memory training. This suggests that the decrease observed in wild-type that dopamine neurotransmission via D2 dopamine receptors mediates the worms expressing the transgene is caused by an as yet unknown CREB- aversive effects of caffeine, and that a non-dopaminergic substrate must be dependent mechanism. We are currently using a candidate gene approach to responsible for mediating caffeine’s rewarding properties. identify kinases that are responsible for CREB activation in C. elegans during long-term memory training for habituation, as well as using a CRE (cAMP response element) reporter gene assay to identify which neurons, within the

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neural circuit that mediates the reflexive response to mechanosensory begins (e.g., Duhamel et al, 2002). So the brain likely uses a fast internal stimuli, undergo changes in CREB-mediated synaptic plasticity. So far we estimate of the eye’s movement. We tested whether the brain relies on the have tested the C. elegans homologues to PKCε, PKCβ, and same internal efferent signals when updating spatial memory as it does to PKA catalytic subunit. All of these kinases tested have shown normal long- guide saccades to their goal. We altered people’s eye control using saccadic term memory for habituation. adaptation, e.g., we trained subjects to saccade only 15° when they saw a This work was supported by operating grants from NSERC to CHR and by target 20° left (i.e., a saccadic amplitude 75% of the seen distance). Within Graduate Fellowships from MSFHR and CIHR to TAT. Kimura Y et al. 20 trials, subjects were producing leftward saccades that undershot the 1st (2002). EMBO reports, 3:962-966.; Rose JK, Kaun KR, Chen SH, Rankin target’s initial seen location by 73-77%. The visual feedback however, CH (2003). Journal of Neuroscience, 23:9595-9600. indicated that the eyes had gone the whole distance, e.g. 20° left. The subjects’ task was to then saccade towards a second, remembered target (which had been briefly flashed before they made their leftward movement). 60 D110 The 2nd target was always located to the right of the 1st because adapting NEURONAL ACTIVATION DURING FOOD ANTICIPATORY leftward saccades leaves rightward ones unchanged. We examined error ACTIVITY IN RAT patterns to the 2nd remembered target to determine if updating was also Anne-Marie Poulin, Elena Timofeeva*. Centre de recherche de l’Hôpital impaired in the same way as adapted saccades. That is, do subjects update the Laval, Université Laval, Québec 2nd target by 20°, computing eye position of the 1st target based on its initial seen location, and subsequently overshoot the true location of the 2nd target? Food anticipatory activity (FAA) is developed in rats when food is Or do they compensate for the shorter adapted saccade based on actual restricted to a few hours daily. FAA is characterized by increasing of efferent signals for that movement, and land accurately on the 2nd target site? locomotor activity during 2-3 hours preceding food access. The mechanisms Our results suggest that subjects partly compensated for the induced adapted underlying the food-entrained oscillator (FEO) remain elusive. Detection of saccade when updating the location of the 2nd target, landing closer to the c-fos expression in the brain during FAA may help to reveal the role of brain actual target site than to the location predicted if the brain had misestimated structures involved in the FEO. Methods: All rats were maintained under a the 1st saccadic amplitude. This incomplete compensation suggests that the 12:12h light/dark cycle (lights on between 6h00 and 18h00). During three estimate of eye motion being updating was influenced by the seen distance weeks two groups of rats (AL1 and AL2) were fed ad libitum, while other of the 1st target. These findings suggest that the brain relies mostly, but not rats were subjected to restricted scheduled feeding. All rats maintained on exclusively, on feedback from signals that guide the actual eye movement scheduled feeding had the access to food between 12h00 and 14h00. On when updating spatial memory. fourth week food-restricted rats were sacrificed during FAA 3 hours (food- anticipated, FA3), 2 hours (FA2), 1 hour (FA1) and 0 hour (FA0) before scheduled feeding or after one hour of feeding (refed, RF1). Ad libitum fed 62 D112 groups, AL1 and AL2 were sacrificed simultaneously with respectively FA3 TEMPORAL DYNAMICS OF SACCADE COMMANDS IN and FA0 groups. Plasma insulin and corticosterone levels as well as the MONKEY SUPERIOR COLLICULUS DURING IMMEDIATE expression of c-fos mRNA in the brain were analyzed. Results: Plasma INSTRUCTION SWITCHING OF PRO AND ANTISACCADES corticosterone was significantly increased during FAA. This increase in Watanabe M. and Munoz D.P. Centre for Neuroscience Studies, Queen’s corticosterone levels was reversed by feeding. In contrast, the levels of University, Kingston insulin were decreased during FAA and raised upon feeding. In the brain we have found particular patterns of c-fos mRNA expression during food Our ability to flexibly respond to a sensory event has been extensively anticipation and feeding. Expression of c-fos mRNA in two regions, the examined by psychophysical experiments: behavioral performance is worse nucleus of the solitary tract (NTS) and the magnocellular part of the when the instruction switches across consecutive trials than when it repeats. paraventricular hypothalamic nucleus (PVHm), was increased after feeding The purpose of this study is to map this phenomenon onto the dynamics of but not during FAA. In the dorsomedial hypothalamic nucleus c-fos mRNA neural circuits by neurophysiological experiments in awake, behaving was highly expressed in the dorsal part during FAA and in the ventral part monkeys performing a psychophysical paradigm. After monkeys maintained after feeding. FAA increased c-fos expression in the lateral hypothalamus, their eyes on the central fixation point (FP), a visual stimulus was turned on anterodorsal thalamic nucleus and septohippocampal nucleus. During FAA c- at 15° left or right from the FP. Based on the color of the FP, the monkeys fos also expressed in the parvocellular PVH that in concert with significant were required to make a saccade to the stimulus (prosaccade) or to the increase of plasma corticosterone suggests the activation of the hypothalamic opposite direction of the stimulus (antisaccade). In 33 or 50 % of trials, the pituitary adrenal (HPA) axis. The activation of suprachiasmatic nucleus color of the FP switched after stimulus onset and the monkeys were required (SCN) and the anterior paraventricular thalamic (PVTa) nucleus during FAA to follow the second instruction. In switch trials, the monkeys’ responses preceded that of the parvocellular PVH. The present data provide evidence were dominated by error saccades based on the first instruction. However, as for early induction of expression of c-fos mRNA in the SCN and PVTa and reaction times increased, the dominant response switched from error following HPA axis activation during food anticipation. saccades to correct saccades. We quantified the time period from a switch time to the time when the dominant response switched (Switch Signal Reaction Time: SSRT). SSRTs were approximately 220 ms across the 61 D111 monkeys and conditions. To identify the temporal dynamics of neural activity ESTIMATING THE SIZE OF EYE MOVEMENTS FOR UPDATING during this paradigm, we recorded the activity of saccade related neurons in SPATIAL MEMORY the superior colliculus (SC). When the monkeys had to cancel a saccade Lia E Tsotsos and Denise YP Henriques. School of Kinesiology of Health toward the movement field of neurons after instruction switching, Science, Centre for Vision Researh, York University suppression of activity occurred earlier than behaviorally estimated SSRTs + switch times (-46 ms and -24 ms from the behavioral estimates for pro and To maintain a stable perception of the world, our brain must update our antisaccade cancellation, respectively). However, when the monkeys representation of visual space each time our eyes move. But when the brain reprogrammed a saccade toward the movement field of neurons after updates spatial memory during eye movements, how does it estimate the size instruction switching, activation of the neurons occurred almost at the same and direction of those movements? We know that some updating actually time with the behavioral estimates (-8 ms and -1 ms from the behavioral precedes the eye movement: neurons in various brain regions code the estimates for pro and antisaccade reprogramming, respectively). These predicted post-movement retinal locations of objects before the movement results suggest that, at least at the level of the SC, the two processes occur in

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serial order: cancellation of a saccade based on the first instruction and achieve criterion on the shift than controls. Surprisingly, AMPH treated rats reprogramming of a saccade based on the second instruction. learned the reversal faster than controls, but required a greater number of probe trials to complete the task, indicating an impairment in the ability to apply the learned rule to a new context. Viewed collectively, these results 63 D113 suggest that repeated AMPH exposure can enhance behaviour flexibility DETERMINING THE ROLE OF THE PREFONTAL CORTEX IN assessed in this manner, but impairs applying rules to a new situation. These SUPPRESSION OF REFLEXIVE SACCADES effects may be attributable to deficits in latent inhibition, in that AMPH S. Wegener*(1), K. Johnston(2), S. Everling(1,2). (1) Department of treatments may have impaired learning to ignore task-irrelevant stimuli, Physiology and Pharmacology, University of Western Ontario, London (2) facilitating learning new stimulus-reward associations when those stimuli Robarts Research Institute, London become relevant.

The prefrontal cortex (PFC) has been implicated in the ability to perform complex behaviours requiring the implementation of cognitive control. 65 D115 Theories of PFC function have suggested that this area participates in EVIDENCE THAT GRIP SCALING, BUT NOT PERCEPTUAL cognitive processes via a top-down control mechanism. Top-down control ESTIMATION, RESISTS THE PONZO ILLUSION has been extensively investigated in both humans and primates using the Marla E. Wolf*, Robert L. Whitwell*, Thida Han, and Melvyn A. Goodale. antisaccade task. In this task, subjects are required to produce a rapid eye Department of Psychology, University of Western Ontario movement in a direction opposite to a suddenly appearing visual stimulus. Correct performance of this task requires that the subject inhibits the Compelling evidence for dissociations between vision-for-perception and automatic tendency to look toward the stimulus location (prosaccade). Here, vision-for-action has come from psychophysical studies in healthy subjects we investigated whether PFC microstimulation impacts behavioural showing that pictorial illusions, which by definition have robust effects on performance and saccadic reaction time. We applied microstimulation at 35 perception, have little or no effect on precision grasping in the right hand. PFC sites while a single monkey performed a paradigm of randomly Critics have argued, however, that the task demands for grasping are quite interleaved prosaccade and antisaccade trials. Stimulation occurred on 50% different from those required for perceptual judgments. When a participant of the trials and was aligned to stimulus onset. Behavioural performance and reaches out to grasp an object, they have argued, he or she need only attend saccadic reaction times were recorded. For 43% of the PFC sites, to one of the targets. When making a perceptual judgment, however, the microstimulation significantly affected behavioural performance and/or participant typically attends to both targets in the illusory display. To saccadic reaction time. Across all stimulation sites, we found that PFC circumvent this issue, we carried out a study in which only one target was microstimulation resulted in significantly shorter reaction times for presented at a time, placed in different positions within a Ponzo illusion. contralateral prosaccades, and significantly longer reaction times for When the target is placed where the lines in the display converge, it typically ipsilateral prosaccades and ipsilateral antisaccades, when the stimulus was appears larger than when it is placed at the diverging end of the display. presented to the contralateral field. In addition, there were significantly more Participants were asked to perform two tasks: an Action task, in which they ipsilateral antisaccade errors during PFC stimulation. These results support a were simply asked to reach out and pick up the target (a small disk that varied role for PFC in reflexive saccade suppression. in size from trial to trial), and a Perception task, in which they were asked to keep their hand in a stationary position on the start button and to indicate the perceived size of the disk by opening their index finger and thumb a 64 D114 matching amount. The results were clear. Peak grip aperture (PGA) in the DIFFERENTIAL EFFECTS OF CHRONIC AMPHETAMINE Action Task was not influenced by the Ponzo display. In other words, TREATMENT ON SET SHIFTING AND REVERSAL LEARNING participants maintained a constant PGA for a given target size regardless of Jennifer M. Whelan, Desirae M. Haluk, and Dr. Stan B. Floresco. The where it was placed on the illusory background. In contrast, the Manual University of British Columbia- Psychology department Estimation Aperture (MEA) in the Perception task was affected by the Ponzo display; participants estimated the target to be larger when it was placed at Psychostimulants such as amphetamine (AMPH) promote the release of the converging as compared the diverging end of the display. This dopamine, but chronic exposure to these drugs can induce long-term negative dissociation between the effects of the illusion on Action and Perception effects that disrupt prefrontal cortex function. For example, Fletcher et al. tasks remained significant even when the scores were adjusted for (2005) examined the effects of chronic AMPH treatments on behavioural differences in the sensitivity (slopes) of the two measures. Furthermore, no flexibility using a set shifting task where Sprague Dawley rats were trained differences in within-subject variability were observed between the action to dig for food in one of two bowls that could be discriminated on the basis and perception tasks. Taken together, the results suggest that the relative of either texture or odour. Repeated AMPH treatment impaired insensitivity of the visuomotor system to pictorial illusions cannot be extradimensional set shifting and subsequent reversal learning, suggesting explained by appealing to differences in attention, precision, and/or the that these treatments may alter the functioning of the medial and orbital relative sensitivity of grip scaling vs. manual estimation to changes in target prefrontal cortex. To explore the issue further, the present study examined the size. effects of chronic AMPH sensitization on behavioural flexibility using a cross-maze set-shifting task. Long Evans rats were initially habituated to the maze, after which they received 15 AMPH or saline injections (1-5 mg/kg 66 D116 every 2nd day, increasing the dose by1 mg every 3rd injections). Following DIFFERENT EFFECTS OF AGE AND OF CHRONIC STRESS IN a 2 week drug wash-out period, rats were trained on a series of BEHAVIOUR IN THE FORCED SWIM TEST IN FEMALE AND discriminations to receive food reward. Rats received 40 trials per day until MALES RATS they achieved criterion performance of 10 correct consecutive choices, A Wilton, A Harrison, E Tourountzas, & CM McCormick. Brock University followed by a probe trial, where they were released from a different start Department of Psychology and Centre for Neuroscience location on the maze. Rats were initially trained on a visual-cue discrimination. On the strategy shift, rats were trained to use a response We previously reported that social stress in adolescence (SS; daily 1 h strategy (e.g. always turn left, ignore the visual cue). For the reversal, rats isolation and change of cage partner from day 30 to day 45 of age) increased were trained to reverse their turn direction. AMPH treatment did not impair behavioural responses to psychostimulants in females, but not males learning of the initial cue discrimination, nor did it alter performance during (McCormick et al., 2004, 2005). Here we investigated whether SS in the set shift. In fact, AMPH treated rats tended to require fewer trials to adolescence would increase depressive behaviour as measured in the Porsolt

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forced swim test (FST). The SS group and a comparison group that 68 D118 underwent swimming only (CTL) were tested on day 45 of age. To test the INDIVIDUAL DIFFERENCES IN CONTEXTUAL FEAR enduring effects of SS, a separate group of SS and CTL were tested on day CONDITIONING ASSOCIATED WITH NATURAL VARIATIONS IN 70 of age. FST involves a 15 min swim in a cylindrical tank of water (260C) MATERNAL CARE ARE NOT REVERSED BY ENVIRONMENTAL and 24 h later a 5 min swim in the tank. Behaviours measured during the FST ENRICHMENT IN THE ADOLESCENT PERIOD IN RATS were climbing walls of the tank, swimming, and immobility. Time spent Tie-Yuan Zhang, Rosemary Bagot, Carine Parent, Michael J Meaney.. climbing or immobile were used for statistical analyses. FEMALES: A Douglas Hospital Research Centre, McGill University, Montreal Group X Age X Day X Behaviour ANOVA found the factor of AGE to be significant (F1,54 = 7.63, p = 0.008), whereby adults engaged in less In rats, maternal care influences the development of hormonal and climbing and immobility than adolescents. Age did not interact with any physiological responses to stress. The adult male offspring of Low-licking other factor. Post hoc analysis of the interaction of Group by Days by and grooming (LG) mothers show increased anxiety, spend less time in the Behaviour (F1,54 = 5.27, p = 0.026) indicated that on Day 1, SS was more centre of a novel open field and show impaired spatial learning in the Morris immobile (p = 0.04) with less climbing (p = 0.01) than CTL, but the groups water maze compared to the offspring of High-LG mothers. Environmental did not differ on day 2. Whereas CTL had a significant increase in immobility enrichment has been reported to reverse the effect of maternal care on spatial (p < 0.0001) and a decrease in climbing (p = 0.001) from Day 1 to Day 2, SS learning as well as the effect of maternal separation on the stress response. In did not change from Day 1 to Day 2. MALES: A Group X Age X Day this study, we examined whether maternal care influences contextual fear ANOVAs found an interaction of Group by Age (F1,55 = 5.15, p = 0.03) for conditioning as well as centre exploration time in an open field and whether climbing, with SS males climbing more than CTL for the adults (p = 0.09) environmental enrichment from days 22 to 70 of life can reverse these but not for the adolescents, and with the adolescents climbing more than effects. The results confirmed that maternal LG was correlated with centre adults for the CTL (p = 0.07) but not for SS. For immobility, only the Day time in the open field, and showed that this effect was abolished by by Age interaction was significant (F1,55 = 15.06, p < 0.0001), with adults environmental enrichment. In addition, maternal LG was highly correlated decreasing immobility (p = 0.03) and adolescents increasing immobility from with contextual fear conditioning measured by time spent freezing in the day 1 to day 2 (p = 0.006). These results indicate that females exposed to previously shocked context. Offspring of Low-LG mothers showed enhanced chronic stress in adolescence show increased depressive behaviour in the freezing in the conditioned context compared to offspring of High-LG FST that remains evident several weeks after stress exposure. Age was a mothers. However, enrichment had no observable effect on contextual fear greater factor for FST behaviour in males, with adolescent males appearing conditioning. The results suggest that maternal care exerts an important more prone to depressive behaviour than adults, and a history of chronic influence on learning and memory processes associated with aversive events, stress tending to increase vigorous “non-depressive behaviour” (climbing) in and these effects, unlike spatial learning and anxiety measured in the open adult males. field, are not reversed by environmental enrichment in the adolescent period. Supported by CIHR 67 D117 A COMPARISON OF SACCADE AND POINTING TOPOGRAPHY 69 D119 BETWEEN MEDIAL AND LATERAL AREAS IN THE HUMAN IMPAIRMENT OF HIPPOCAMPAL NEUROGENESIS IN POSTERIOR PARIETAL CORTEX DIABETIC RATS John Zettel(1), Tutis Vilis(2), Jody Culham(3), Doug Crawford(1,4). 1 W-J. Zhang*, Y-F. Tan, J. I.T. Yue, M. Vranic, J.M. Wojtowicz. Department of Centre for Vision Research, York University, 2 Department of Physiology and Physiology and Department of Medicine, University of Toronto, Toronto Pharmacology, University of Western Ontario, 3 Department of Psychology, University of Western Ontario, 4 Department of Psychology, York University Adult neurogenesis in the dentate gyrus is an evolutionarily preserved trait in most mammals examined thus far. Neuronal proliferation and Previous functional magnetic resonance imaging (fMRI) studies subsequent integration of new neurons into the hippocampal circuit are identified areas in the posterior parietal cortex (PPC) that are active during regulated processes that can have profound effects on an animal’s behaviour. memory-guided saccades and pointing to visual targets. Both the areas for A streptozotocin model of type I diabetes, characterized by low insulin and saccades and pointing are lateralized, showing higher activation for actions high plasma glucose levels, affects not only the body’s overall metabolism directed toward the contralateral hemifield (Medendorp et al., 2003, Journal but also brain activity. We report here that seven weeks after the onset of of Neuroscience; Fernandez-Ruiz et al., in press, Cerebral Cortex). The uncontrolled diabetes, neuronal production is dramatically reduced. purpose of this study was to clarify topographical areas of activation in the Neurogenesis was measured within the dentate gyrus of the hippocampus PPC related to saccading to and pointing to remembered targets as well their using standard immunohistochemical markers Ki67, Doublecortin, Calbindin activity in an anti-pointing task. fMRI was used to measure the blood and BrdU. Cell proliferation was reduced by 46% and neuronal maturation oxygenation level-dependent response while right-handed individuals either was reduced by 53% for a combined reduction of neuronal production of made saccades or pointed to remembered visual targets in a blocked design. 75%. Such reduction is expected to cause a significant functional impairment Subjects also performed an anti-pointing task. Contrasts between right- and of learning and memory in the diabetic animals. These results may shed light left-visual targets revealed topographic areas related to each effector. The not only on causes of diabetic neuropathy but also provide an explanation for saccade task produced lateralized activation in the medial intraparietal sulcus the proposed beneficial therapeutic effects of exogenous insulin on memory (IPS; left Talairach coordinates (TC): -23, -60, 43). The pointing task functions. Supported by CIHR produced topographic activation in a medial region of the PPC (left TC: -12, -82, 32), near the superior parieto-occipital sulcus, as well as the IPS region activated by saccades. These two regions are consistent with previous 70 D120 studies. In addition, a previously unidentified area in the precuneus also PREPULSE INHIBITION OF STARTLE: TIMING OF GLYCINE demonstrated topography for pointing (left TC: -8, -59, 57). These results ALPHA1, GABAA AND GABAB MEDIATED INHIBITION IN MICE show that a region in the IPS has topographic activity for visually directed Alex Djedovic, Nyresa Alves, Susanne Schmid, Daniel Bosch, Gavin Tse, saccades and pointing, while a more medial region is topographically John Peever, John Yeomans. Centre for Biological Timing and Cognition, activated by pointing alone. Examination of activity in these and other Departments of Psychology and Cell and Systems Biology, University of topographically organized areas during an anti-pointing task are expected to Toronto, Toronto M5S 3G3 provide further insight into their role in visuospatial behavior.

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Prepulse inhibition (PPI) involves midbrain pathways for approach 72 D122 responses that inhibit giant neurons in the caudal pons that elicit startle. PPI THE ROLE OF SEXUAL ORIENTATION IN FACE RECOGNITION is mediated largely by muscarinic and GABAB receptors in the pons at Paul Brewster*, Caitlin Mullin and Jennifer Steeves. Department of interstimulus intervals (ISIs) of 100-500 ms in rats and mice, but little is Psychology and Centre for Vision Research, York University, Toronto, ON known about receptors mediating PPI at ISIs of 10-50 ms. We found that the GABAA blocker, bicuculline (1 mg/kg i.p.) reduced PPI at ISIs of 30 and 50 Previous research has suggested a sex difference in face recognition ms, but not at 4-20 ms, ISIs where PPI in B6 mice is especially strong (over ability such that women tend to outperform men. Recent evoked potential 50%). Glycine α1 receptor transgenic mice with reduced glycine research has shown gender effects with men displaying more right lateralized function (Becker et al, 2002) showed stronger startle responses than B6 wild- activation while women are more bilateral in face processing, suggesting type mice, but much less PPI at a wide range of ISIs from 4-300 ms. gender differences in face processing at a cortical level. Although gay men Bicuculline blocked most of the remaining PPI in glycine α1 receptor display a cross-sex shift in some sexually dimorphic tasks—with their mutant mice at ISIs of 30 and 50 ms. In temporal order, then, PPI in B6 mice performance resembling that of female participants—the implications of this depends on glycine α1, GABAA, and finally, both muscarinic and for face recognition tasks not been measured. The current study examined the GABAB receptors. These ISI-specific effects of blockers on PPI in mice are performance of homosexual men on a basic old/new face recognition task related to transmitters (glycine, GABA and acetylcholine) and receptors compared to heterosexual men and women. Twenty four women, 22 mediating inhibition of giant neurons in the pontine reticular formation. heterosexual men and 11 homosexual men were tested. Participants learned five male and five female faces and subsequently were tested for accuracy and latency of recognition for the learned faces among a set of 30 unlearned 71 D121 faces. Overall, latencies of heterosexual men were significantly higher than DEVELOPMENT OF ROBUST INTRAVENOUS NICOTINE SELF- those of women, and latencies of gay men fell between those of heterosexual ADMINISTRATION BEHAVIOR IN DRUG-NAIVE SQUIRREL male and female participants. The sex of visual face images also produced an MONKEYS WITH NO EXPERIMENTAL HISTORY UNDER FIXED- interaction such that gay men’s latencies for female face images were RATIO AND PROGRESSIVE-RATIO SCHEDULES OF comparable to those of female participants, while latencies for male face REINFORCEMENT images were comparable to those of heterosexual men. Observed sex Bernard Le Foll1 and Steven R. Goldberg2. 1 Translational Addiction differences in overall latency are consistent with previous visual cognitive Research Laboratory, Centre for Addiction and Mental Health, 33 Russell studies showing participant gender effects on face recognition. The shorter Street, Toronto, ON M5S 2S1. 2 Preclinical Pharmacology Section, latencies of gay men compared to those of heterosexual men suggest Behavioral Neuroscience Research Branch, Intramural Research Program, neurobiological correlates of homosexuality that may be evidenced in face National Institute on Drug Abuse, National Institutes of Health, Department processing. of Health and Human Services, Baltimore, Maryland, USA

Nicotine, a psychoactive component of tobacco plays a major role in 73 D123 smoking dependence, but reinforcing effects of nicotine that contribute to SEASONAL VARIATION IN HIPPOCAMPAL NEURON smoking dependence have been difficult to demonstrate directly in past RECRUITMENT IN THE FOOD-STORING BLACK-CAPPED controlled laboratory studies with both animals and humans as experimental CHICKADEE subjects. Although the ability of nicotine to act as a reinforcer in Jennifer S. Hoshooley, David F Sherry. Program in Neuroscience, University experimentally naïve rodents has been demonstrated under limited of Western Ontario, London, ON N6G 2V conditions, its ability to act as a reinforcer in experimentally naïve non- human primates is still unclear. In the present experiments, intravenous Black-capped chickadees store food in a seasonally-varying fashion with nicotine self-administration behavior developed in drug-naive squirrel a peak in storing activity in the fall and winter. Previous research has shown monkeys with no history of operant behavior training and no setting that these birds retrieve stored food by remembering the spatial locations of conditions such as food deprivation. Once self-administration behavior large numbers of spatially-dispersed caches. Memory for cache sites is developed, nicotine sustained robust responding under a Fixed-Ratio hippocampus-dependent. We have recently described a mid- to late-winter schedule of reinforcement where 10 lever presses were required to produce peak in the recruitment of new neurons into the chickadee hippocampus each intravenous injection. The behavior was under the control of nicotine using the cell-birth marker BrdU. There was no indication of seasonal injections since lever pressing extinguished when the nicotine solution was variation in neuronal recruitment into the anatomically adjacent changed to saline solution and varying the injection dose of nicotine resulted hyperpallium apicale. Further results show that new neurons are incorporated in a typical inverted U-shaped dose-response curve. Nicotine self- into the hippocampus of the black-capped chickadee at a much higher rate administration behavior also maintained at high rates under a Progressive- than into the hippocampus of the non-food-storing house sparrow. Ratio schedule of reinforcement and varying nicotine dose again resulted in Chickadees also had a greater total number of hippocampal neurons in spring an inverted U-shaped dose-response curve. These results demonstrate that than in fall, a seasonal difference not found in house sparrows. Taken nicotine can function as a prototypic drug of abuse serving as a robust together, these results suggest that hippocampal neuronal recruitment may reinforcer in squirrel monkeys. This non-human primate represents a contribute to memory for cache sites or to other seasonally-varying valuable animal model for studying the neurobiological basis of nicotine components of food storing behaviour. dependence. Animals used in this study were maintained in facilities fully accredited by the American Association for the Accreditation of Laboratory Animal Care (AAALAC) and all experiments were conducted in accordance 74 D124 with the guidelines of the Institutional Care and Use Committee of the SEXUAL DIMORPHIC EFFECTS OF NEONATAL SYSTEM Intramural Research Program, National Institute on Drug Abuse (NIDA), IMMUNE ACTIVATION WITH LIPOPOLYSACCHARIDE ON THE National Institutes of Health and the Guidelines for the Care and Use of BEHAVIOURAL RESPONSE TO A HOMOTYPIC ADULT IMMUNE Mammals in Neuroscience and Behavioral Research (National Research CHALLENGE Council, 2003). Research was supported by the Intramural Research Program Christine M. Tenk, Martin Kavaliers, Klaus-Peter Ossenkopp. Graduate of the NIDA, NIH, DHHS. Program in Neuroscience and Psychology Department, University of Western Ontario, London, Ontario, Canada

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Research has shown that acute immune activation during the early ability to acquire new interneurons throughout life. It is therefore a postnatal period with the gram negative endotoxin, lipopolysaccharide particularly appropriate region for studying the role of experience in (LPS), alters a variety of physiological and behavioural process in the adult sculpting a neuronal network postnatally. Interestingly, interneurons arriving animal. For example, neonatal LPS exposure affects disease susceptibility to the adult OB differentiate into distinct neuronal types, including later in life though these effects appear to be modulated by time of exposure, GABAergic cells located in the granule cell layer and a diverse set of neurons gender, and immune stimulus. The current study examined sex differences in in the glomerular layer comprising also GABAergic and dopaminergic the effect of neonatal LPS treatment on the hypoactivity response to adult interneurons, as well as other neuronal subtypes expressing calretinin and LPS administration. Male and female Long-Evans rats were treated calbindin. To investigate the potential role of afferent activity in the fate systemically with either LPS (50µg/kg) or saline (0.9%) on postnatal days 3 specification program of OB newborn cells, we performed unilateral nostril and 5. Later in adulthood (postnatal day 92), all animals were subjected to occlusion in adult mice. We explored the number, density and proportion of an adult LPS challenge and were injected (i.p.) with 200µg/kg LPS. Two chemospecific newly generated cells in the odor-deprived animals. To hours after injection, animals were placed in a non-novel open-field and understand whether sensory activity plays a role in the acquision and/or locomotor activity was assessed for 30 min. Body weights were determined maintenance of chemospecific phenotype, we analyzed the cells born 21 days both at time of injection and 24hr later to examine LPS-induced weight loss. before or 21 days after sensory deprivation. Our analysis demonstrates, in Adult males treated neonatally with LPS exhibited significantly less agreement with previously reported results, that sensory deprivation resulted horizontal and vertical activity in response to the LPS challenge relative to in drastic reduction of the number of dopaminergic periglomerular cells. This males treated neonatally with saline. This effect was not observed in females. effect was specific to the dopaminergic cells, since neither calbindin-positive Thus, the current study revealed that neonatal LPS exposure potentiates the nor calretinin-containing periglomerular cells were affected. Surprisingly, adult hypoactivity response to a homotypic immune challenge in rodents. however, unilateral sensory deprivation also induced a drastic up-regulation These findings may be related to sexually dimorphic effects of neonatal LPS of the density of cells expressing Pax6, a transcriptional factor known to be on the hypothalamic-pituitary-gonadal axis and the immunoenhancing involved in the dopaminergic phenotype specification in the adult OB. Our effects of estrogen. These findings have potential clinical significance given results suggest that the adult OB is a highly plastic structure, which attempts that neonatal exposure to pathogens is a fairly common occurrence and gram- to compensate for the dopaminergic cell loss by up-regulating the number of negative bacteria are a common cause of neonatal bacterial infections. Pax6-positive cells.

77 B403 DEVELOPMENT INSULIN-LIKE GROWTH FACTOR 1-STIMULATED PROTEIN SYNTHESIS IN OLIGODENDROCYTE PROGENITORS Olivia Bibollet-Bahena and Guillermina Almazan. Pharmacology and 75 B401 Therapeutics Department at the McGill University A POTENTIAL ROLE FOR MICROGLIA IN NEURODEVELOPMENTAL DISORDERS Several lines of investigation have provided evidence that insulin-like *Joseph M. Antony, Freda Miller. Developmental and Stem Cell Biology, The growth factor-1 (IGF-1) is essential for oligodendrocyte (OL) development, Hospital for Sick Children, Toronto promoting their proliferation, survival and differentiation. Moreover, IGF-1 null mutant mice have a decreased number of OL progenitors (OLPs) and Microglia are resident hematopoietic cells that play a key role in CNS myelination. IGF-1 interacts with its receptor to activate two main neurodegeneration and neural injury in the adult nervous system. However, transduction pathways, the PI3K/Akt and the Ras-Raf-MEK/ERK cascades, apart from its predominant role in regulating developmental cell death, the which mediate survival or proliferation of OLPs. The objective of this study role of microglia in normal brain development remains an open question. To was to elucidate the signalling pathways mediating IGF-I-stimulated protein investigate its role in developmental disorders, we quantified microglia in the synthesis, important for growth and differentiation of OLs. In other cellular hippocampus of newborn Noonan Syndrome mice and found that there was systems, the PI3K/Akt pathway is involved in protein translation. a 4-fold increase in the number of microglia relative to age-matched wild Furthermore, mTOR and the p70 S6 kinase are downstream effectors that type littermates. In cortical precursor cultures from E12.5 mice, microglia are phosphorylate translation initiation factors (e.g. eIF-4E) and their regulators present at 0.2% and increasing them to 0.8% perturbed cells numbers and (e.g. 4E-BP1). OLPs, obtained from primary cultures, were treated with IGF- differentiation. This effect could be further mimicked by conditioned 1 with or without pharmacological inhibitors for PI3K (LY294002 or medium from developing microglia. Further, ablating microglia from our wortmannin), mTOR (rapamycin), Akt (III or IV), ERK (PD09859), PKC control cortical precursor cultures caused a decrease in total numbers of (bisindolylmaleimide) and an adenovirus with dominant negative Akt. precursors and neurons, suggesting the role of soluble factors in this process. Protein synthesis was assessed by metabolic labeling with 35S-methionine, In order to examine if microglial proliferation and activation comprises a and kinase activation by Western blotting. IGF-1-stimulated protein synthesis common them in various neurodevelopmental disorders, we are examining was dose-dependent and required PI3K, mTOR, Akt, ERK and PKC the microglial population in the mouse model for Fragile X. Preliminary activation. Concordantly, Western blotting revealed that IGF-1 stimulates results suggests that glial development in fmr1 knockout mice is altered. The phosphorylation of Akt, mTOR, ERK, S6 and 4E-BP1. Activation of S6 and molecular mechanisms neural cell development and the role of microglia in inactivation of 4E-BP1 occur through phosphorylation and are required for this regard is being investigated. protein synthesis to take place. These events are dependent on the upstream activation of PI3K, Akt and mTOR. Project funded by the MS Society of Canada. 76 B402 ROLE OF SENSORY ACTIVITY IN THE FATE SPECIFICATION OF NEWLY GENERATED CELLS IN THE ADULT OLFACTORY BULB Pierre-Olivier Bastien-Dionne*, Andre Parent and Armen Saghatelyan. Centre de recherche Universite Laval Robert-Giffard, Quebec

During development and shortly after birth, neuronal activity contributes to the organization of the nervous system. The adult olfactory bulb (OB), which is the first-order sensory relay for olfactory processing, retains the

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78 B404 that not all motoneurons had yet reached their final position. Glutamate, SKIN-DERIVED PRECURSORS (SKPS): IN VIVO CELL FATE IS GABA and glycine are present in spinal neurons of newborn but increase LIMITED TO THE NEURAL CREST LINEAGE, AND IS postnatally. There are very few synapses in the spinal enlargements of DETERMINED BY TISSUE-SPECIFIC FACTORS newborn; synaptogenesis is mostly a postnatal event that occurs along J. Biernaskie*1,2 and F. D. Miller1,2,3,4. 1Depts of Dev Biology, and 2Brain rostrocaudal and ventrodorsal gradients, in accordance with the mostly or and Behavior, Hospital For Sick Children Research Institute; 3Depts of entirely postnatal growth of propriospinal and descending systems into the Physiology and 4Medical Genetics, University of Toronto cord. Therefore, the forelimb movements of newborn are presumably the expression of the spinal central pattern generator. A study of spinal Skin-derived precursors (SKPs) are a neural crest-related precursor found spontaneous activity and of the gap junction protein connexin is underway. in both rodent and human postnatal dermis, where they reside within a hair The limbs of newborn contain few cholinergic terminals, which have the follicle dermal papilla niche. In culture, SKPs are multipotent, generating appearance of growth cones; their motor innervation proceedes mostly both mesodermal cells and those with peripheral neural characteristics. postnatally, especially the hindlimbs. Myelinogenesis in the spinal However, their differentiation potential in vivo has not been explored. Here, enlargements and the corresponding ventral and dorsal roots only starts in the we asked whether SKPs are multipotent in vivo, and whether their tissue 2nd week and continues for months, in accordance with the protracted environment influences their differentiation potential. To perform these development of locomotion. experiments, SKPs were generated from dermis of neonatal (P1-P3) YFP- expressing mice and adult YFP-expressing rats. These YFP-positive SKP spheres were transplanted into either the dermis or the sciatic nerve of adult 80 B406 NOD-SCID or immunosuppressed Shiverer mice (deficient in myelin basic INSIGHTS INTO OLIGODENDROCYTE AND MYELIN protein gene), respectively. Six weeks following transplantation, SKPs GENERATION GAINED FROM THE ANALYSIS OF HUMAN transplanted into the skin had integrated throughout the thickness of the EMBRYONIC AND ADULT PLATELET-DERIVED GROWTH dermis, and were present within the dermal papilla and dermal sheath of hair FACTOR RESPONSIVE NEURAL PRECURSORS follicles, suggesting that they were able to re-enter their original niche. SKPs Andrew Chojnacki*, John Kelly, Walter Hader, and Samuel Weiss. integrating into dermis expressed appropriate dermal cell markers, and did Hotchkiss Brain Research Institute, Department of Cell Biology and not express markers of inappropriate cell types (ie. neurons or peripheral Anatomy, University of Calgary, Faculty of Medicine, Calgary glia). Moreover, SKPs were never seen to contribute to epidermal components of the skin or hair follicle. In contrast, when SKPs were Understanding human oligodendrocyte precursors and their potential to transplanted into the injured sciatic nerve, they integrated within the nerve contribute to remyelination therapies has been limited by an inability to where they differentiated into myelinating Schwann cells and cells with isolate and propagate these cells in culture. We have recently found that the characteristics of perineurial fibroblasts. However, they never expressed neurosphere culture system can be used to isolate and expand mouse markers characteristic of hair follicle dermal papilla or sheath cells, nor did embryonic platelet-derived growth factor (PDGF)-responsive neural they differentiate into cells with characteristics of neurons. Thus, SKPs precursors (PRPs), which predominantly produce myelinating differentiate in vivo to both neural and mesodermal phenotypes, but their oligodendrocytes. Thus, we adapted the identical neurosphere culture system differentiation is apparently restricted to cells of neural crest lineage. The for the study of human embryonic and adult PRPs. Human embryonic PRPs finding that SKPs differentiate into non-overlapping subsets of cells within generated neurospheres that contained a large proportion of the dermis versus the sciatic nerve indicates that tissue environment plays a oligodendrocytes, some of which expressed myelin basic protein, neurons key role in restricting and/or determining their differentiation into tissue- and a small number of astrocytes. In the presence of PDGF, fibroblast appropriate cell types, much as it does for embryonic neural crest stem cells. growth factor 2 (FGF2) promoted human embryonic PRP expansion for several generations. In contrast, embryonic epidermal growth factor- and FGF-responsive neural stem cells rarely generated oligodendrocytes and 79 B405 several lines of evidence suggest that they are phenotypically distinct from THE ONTOGENIC DEVELOPMENT OF MAMMALIAN MOTOR embryonic PRPs. In comparison to their embryonic counterparts, adult SYSTEMS USING A MARSUPIAL human PRPs isolated from corpus callosotomies required twice the culture Pflieger JF*, Lamoureux S, Lavallée A, Lemieux M, Cabana T. period to generate neurospheres, which contained oligodendrocytes and Département de sciences biologiques, Université de Montréal astrocytes, but not neurons. Strikingly, adult human PRPs did not self-renew even in the presence of FGF2. This study suggests that differences in the By using Monodelphis domestica, an opossum born more immature than self-renewal properties of embryonic and adult human PRPs may contribute eutherians, motor systems development can be largely studied postnatally to limited, intrinsic remyelination in adult humans. Moreover, expandable without constraint of the uterus or marsupium, the species being pouchless. human embryonic PRPs may be useful for transplantation therapies aimed at Newborn measure 10mm snout-rump and weigh 100mg. Their forelimbs are remyelination. Supported by the Neuroscience Canada Foundation and the just sufficiently developed to perform rhythmic, alternate movements that, Multiple Sclerosis Society of Canada. together with the trunk that sways from side to side, allow the animals to climb on the mother from the birth canal to a nipple where they attach. The hindlimbs are little more than immobile buds and only start moving in the 81 B407 2nd week. The limbs of newborn comprisde immature cartilaginous bone A TRYPTOPHAN HYDROXLYASE 1 TRANSGENIC REPORTER models surrounded by loose muscle fibers, except in the foot where no DETECTS ABNORMALITIES IN THE DEVELOPING muscle tissue is formed; the connective tissue is mesenchymous. The spinal SEROTONERGIC SYSTEM OF MICE CARRYING THE enlargements, especially at lumbar levels, are very immature: the large ANOREXIA (ANX) MUTATION central canal is surrounded by thick ventricular and intermediate zones in Michael L. Huynh, Elena Rivkin, Sabine P. Cordes*. Samuel Lunenfeld which cells are small, many having the appearance of migrating cells, and a Research Institute, Mt. Sinai Hospital, Toronto, Department of Molecular thin marginal zone. Mitotic figures are seen at lumbar levels, probably of Genetics, Univeristy of Toronto glial rather than neuronal precursors. Motoneurons are recognized by their position and their slightly larger size, but are undifferentiated and form a The wide spread projections of the serotonergic (5-HT) system modulate continuous mass bordering the ventral horn. They express choline emotion-influenced behaviors, such as appetite and aggression. Not acetyltransferase, the synthetic enzyme of acetylcholine. The number of surprisingly, serotonergic dysfunction has been implicated in human cholinergic neurons in the ventral horn increases until two weeks, suggesting psychiatric disorders. While much has been learned about early specification

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of 5-HT neurons from analyses of mouse mutations, the density, 83 B409 pervasiveness, and heterogeneity of 5-HT neuronal processes have GLUCOSE DEPRIVATION INHIBITS MITOCHONDRIAL complicated the analyses of 5-HT innervation. A transgenic reporter system PROTEIN IMPORT: THE ROLE OF TOM20 in the mouse that labels only a subset of 5-HT neuronal processes during a Nam Phan,1,3, Diana Diec,1,3, Natalya Shulyakova, 1,3, and LR Mills,1,2,3. psychiatrically critical developmental window would help uncover the Department of Physiology1, Faculty of Medicine2, University of Toronto, molecular mechanisms that govern the integrity of 5-HT innervation. Here Division of Genetics and Development TWRI University Health Network3, we have genearated a 5-HT-specific developmentally sensitive reporter line Toronto labeling axons, which uses the 6.1kb upstream promoter region of Tryptophan Hydroxylase I (Tph1) to drive the expression of placental The majority (99%) of mitochondrial proteins is nuclear-encoded and alkaline phosphatase (PLAP) in 5-HT processes. Rather than labeling all 5- must be imported into mitochondria. The import process is complex and HT processes, the Tph1-PLAP reporter labels only a subset of 5-HT neurons dependent on an array of translocases and chaperones localized to the inner and, thereby, facilitates axonal tracing. A second strength of this reporter is and outer mitochondrial membranes. Little is known about protein import in its developmental sensitivity. Tph1 expression peaks at P21 in the mouse and neurons but recent studies have shown that at least one progressive then decreases towards adulthood. We have tested the utility of this reporter neurodegenerative disease (Human Deafness Dystonia) is due to an import by analyzing the onset and region-specific 5-HT anomalies in mice carrying deficit. Previous studies using PC12 cells stably transfected with an inducible the anorexia (anx) mutation. 16-21 day old anx/anx mice are known to mitochondrially-targeted GFP (mtGFP) have established that mitochondrial exhibit selective hyper-innervation of 5-HT neurons throughout the brain, protein import can be inhibited by a variety of sub-lethal stressors, including which contributes to hyperactivity, appetite suppression, and head shaking glucose/glutamine deprivation-reperfusion (GD/R). We hypothesized that behavior. While pan-5-HT immunoreactivity was indistinguishable between overexpression of Tom20, an integral component of the protein import anx/anx and +/+ littermates, the Tph1-PLAP reporter uncovered 5-HT machinery, would increase protein import and ameliorate the GD/R-induced developmental deficits as early as P0 in anx/anx mice. Furthermore, while decline in import. Overexpression of Tom20 was achieved by transfecting pan-5-HT immunoreactivity had previously revealed global 5-HT differentiated PC12 cells with full-length human Tom20 (transfection hyperinnervation, analyses of Tph1-PLAP reporter revealed region-specific efficiencies at 24 hrs was 33% ± 6%). Western blot confirmed that under alterations in the 5-HT system of anx/anx mice. Thus, the Tph1-PLAP basal conditions overexpression of Tom20 significantly increased Tom20 reporter provides a highly sensitive indicator, which should prove invaluable expression and Tom20 import to mitochondria. In these cells mtGFP import in future analyses of the 5-HT system in other mouse mutants. Finally, A also increased; 24hr post-transfection mtGFP levels in mitochondria were developmental role and, thus, sensitivity to developmental perturbations have increased by 29% ± 3% and 38% ± 4% by 48hrs. In normal cells mtGFP been postulated for Tph1. Our work shows that Tph1 expression is highly expression and import were unchanged immediately post-GD but by 24h sensitive to developmental perturbations, and lends further support to the mtGFP import was reduced by 27% ± 3% (assessed by flow cytometry) and importance of Tph1 in psychiatric conditions. 22% ± 4% (assessed by Western blot). The decrease in mtGFP import was sustained; at 48hrs mtGFP import was reduced by 32% ± 5% . Intramitochondrial turnover of mtGFP was unchanged. In these cells levels 82 B408 of endogenous Tom20 declined significantly. Mitochondrial membrane NSF CONTROLS SYNAPTIC GROWTH BUT NOT SYNAPTIC potential and ATP levels were unchanged but ROS levels increased by 71% STRENGTH BY REGULATING DLK/JNK SIGNALING ± 8% and 60% ± 14% versus controls at 24h and 48h post-GD/R. Colin DeMill, Taro Kaneuchi, Toshiro Aigaki and Bryan A. Stewart. Colin Overexpression of Tom20 prior to GD prevented the GD induced decline in DeMill & Bryan Stewart: Department of Biology, University of Toronto at Tom20 expression and reduction in mitochondria, and restored mtGFP Mississauga, Taro Kaneuchi & Toshiro Aigaki: Department of Biology, Tokyo import to levels above controls. Our findings indicate that in neurons Metropolitan University, Tokyo sublethal GD reduces Tom20 expression and causes a sustained decline in Tom20 in mitochondria. This decrease in Tom20 is associated with a N-ethylmaleimide-sensitive factor (NSF) is an ATPase well known for its sustained decline in the import of mtGFP and both effects can be reversed by ability to influence synaptic vesicle traffic by dissociating the SNARE overexpression of Tom20. These findings argue that Tom20 is sensitive to complex of proteins. Recent evidence suggests that NSF also has additional GD and is a key loci at which protein import can be modulated cellular roles. Notably, a dominant-negative version of Drosophila NSF2 induces a remarkable overgrowth of the neuromuscular junction (NMJ), which correlates with disrupted filamentous actin and impaired vesicle 84 B410 mobility. In order to determine which signaling pathways may lead to these INDUCTIBLE EXPRESSION OF MUTANT T1A-BETA 5 SUBUNIT novel phenotypes we undertook genetic interaction analysis to identify loss- IMPAIRS PROTEASOME FUNCTION of-function mutations that could suppress the NSF2-induced NMJ Cheryl A. D’Souza*, Anurag Tandon. Centre for Research in overgrowth. We found that flies bearing heterozygous mutant alleles for Neurodegenerative Diseases, Toronto genes of the jun N-terminal kinase (JNK) pathway, but not the p38 kinase pathway, were potent suppressors of NMJ overgrowth. Suppression of the Parkinson’s disease (PD) is a progressive neurodegenerative disease overgrowth phenotype by mutants of Dual Leucine zipper-bearing Kinase characterized by intracellular inclusions (Lewy bodies) and loss of neurons (DLK) /wallenda indicate that the genetic interaction extends to the top of a in the substantia nigra. While the etiology of PD is poorly understood, conserved MAP kinase pathway. Interestingly, electrophysiological analysis α-synuclein and the ubiquitin-proteasome system (UPS), the major of synapses showing morphological rescue failed to show any rescue of the non-lysosomal pathway for the removal of unwanted proteins via ubiquitin dominant-negative NSF2 physiological phenotypes. These data therefore conjugation, are considered key pathogenetic factors. Defects in the UPS are indicate firstly, a novel interaction between NSF and MAP kinase signaling thought to lead to the build-up of insoluble proteins that disrupt cellular pathways that restrains synaptic growth and secondly, that NSF likely function and ultimately result in cell death. In vitro and in vivo studies have controls synaptic physiology and development by two independent shown that pharmacologic proteasome inhibitors can reproduce some aspects pathways. of PD pathology However, the use of inhibitors is problematic for long-term studies due to high cost, non-specific effects and toxicity. As an alternate approach to examine proteasome dysfunction, we have developed a genetic model of proteasome inhibition. This is a doxycycline-regulated expression system that allows conditional expression of a mutant catalytic β5

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subunit of the proteasome. To create this system, the epitope-tagged wild- transplantation-based remyelination can partially restore axonal molecular type or T1A mutant β5 constructs were inserted into plasmids structure and function, it is not clear whether such therapeutic approaches can containing the tetracycline-responsive element (pTRE) and then transfected be used to achieve functional remyelination in models associated with long into commercially available HEK293 cells (BD Biosciences) which stably term, irreversible myelin deficiency. In this study, we transplanted adult express the Tet-On(TM) regulator plasmid. Stable, double-transfected clonal neural precursor cells (aNPCs) from the brain of adult transgenic mice into cell lines were obtained by screening with hygromycin and G418 for several the spinal cords of adult Shiverer (shi/shi) mice, which lack compact CNS weeks. This system enabled us to examine biochemical changes following myelin. Six weeks after transplantation, the transplanted aNPCs expressed induction of expression and permit examination of the long-term effects of oligodendrocyte markers including MBP, migrated extensively along the proteasome inhibition without the non-specific effects of proteasome white matter tracts of the spinal cord, and formed compact myelin. inhibitors. We have shown that expression of the mutant β5 subunit Conventional and three-dimensional confocal and electron microscopy incorporated into proteasome complexes and impaired proteasome activity in revealed axonal ensheathment, establishment of paranodal junctional both cell lysates and in β5-immunoprecipitated fractions. In addition, complexes leading to de-novo formation of nodes of Ranvier and partial long-term exposure of cells to doxycycline resulted in chronic proteasome reconstruction of the juxtaparanodal and paranodal molecular regions of inhibition. With this model, we can analyze progressive changes in PD- axons based on Kv1.2 and Caspr expression by the transplanted aNPCs. related proteins, such as α-synuclein, that occur with proteasome Electrophysiological recordings revealed improved axonal conduction along inhibition. This genetic model is also being used to test the effects of the transplanted segments of spinal cords. We conclude that myelination of oxidative stress against a background of proteasome inhibition. congenitally dysmyelinated adult CNS axons by grafted aNPCs results in the formation of compact myelin, reconstruction of nodes of Ranvier and enhanced axonal conduction. These data suggest the therapeutic potential of 85 B411 aNPCs to promote functionally significant myelination in CNS disorders GLIAL CELL PROLIFERATION IN RAT SPINAL CORD INDUCED characterized by longstanding myelin deficiency. BY PERIPHERAL NERVE INJURY AND THE RELATIONSHIP WITH NEUROPATHIC PAIN Stefania Echeverry*, Xiang Qun Shi, Ji Zhang. Unité de Neurobiologie 87 B413 cellulaire, Centre de Recherche Université Laval Robert-Giffard, Université MEASURING SEVERED BRAIN’S RECONSTRUCTIVE HEALING Laval, Québec Foerster, AP & Holmes, MJ. Department of Psychiatry & Behavioural Neurosciences, Mcmaetrs University, 1200 Main Street West, Hamilton Glial activation is a typical response of the central nervous system to nerve injury. In the current investigation, we characterized the temporal and spatial Precisely severed adult rat brain tissue, marked by implanting the fine pattern of glial proliferation, one of the most conspicuous features of glial wire cutting device that had been lowered to lesion it, can undergo a activation, in relation to nerve injury-induced neuropathic pain. Using reconstructive type of healing that appears to re-establish disconnected bromodeoxyuridine (BrdU) as a mitotic marker, we analyzed cell axonal trajectories either around the lesion, as detours, or across it (Foerster, proliferation in the spinal cord, identified the phenotype of dividing cells, and 1982). Withdrawing the devices through the lower surface of the fixed brain traced their fate, and correlated these phenomena with behavioural assays of leaves two channels that, in horizontal sections, appear as two holes that the neuropathic pain syndrome. Our results demonstrated that peripheral mark the ends of the cut. The initial injury disconnects intercepted tissue, nerve injury induced an early and transient cell proliferation, on the spinal with minimal displacement. HRP tracing of the rat's severed optic pathway, cord ipsilateral to the nerve lesion which peaked at day 3 post-surgery. The and microelectrode mapping of the superior colliculus, confirmed that its majority of the proliferating cells were Iba-1+ microglia, together with some eventual healing was associated with the re-establishment of appropriately NG2+ oligodendrocyte progenitors, and GFAP+ astrocytes. These newly located, mapped and functioning, retinal connections (Foerster & Holmes, generated cells continued to divide and differentiate over time with the 1999). Considering the opinion that "CNS regeneration" requires heroic response peaking at day 14 post-injury. Microglia were always the interventions which produce bizarre-looking axonal extensions (e.g. Steward predominant phenotype (over 50% of the newly formed cell population). et al., 2003), the orderliness of the reconstructive healing would have caused There was a close temporal correlation between microglial proliferation in it to escape attention if the lesions had not been marked independently of the spinal cord dorsal horn and the abnormal pain responses, suggesting a later axonal events. Histological staining for neurons and axons (browns), contribution of the new microglia to the genesis of the neuropathic pain myelin (normal, blue- green; degenerate, bright blue), and neuroglia and symptoms. blood vessels (pinks) in the same section gives a useful view of brain architecture and its post-lesion changes. Although every structure can heal, they seem to have characteristically different ways of doing it. Lesions of 86 B412 pathways made 2 weeks - eight months previously are being examined now MYELINATION OF CONGENITALLY DYSMYELINATED SPINAL to classify these. Apparent strategies include: (i) crossing the lesion; (ii) CORD AXONS BY ADULT NEURAL PRECURSOR CELLS detouring either closely together around the lesion or bulkily with a more RESULTS IN FORMATION OF NODES OF RANVIER AND normal separation; (iii) interweaving and abrupt bending on the proximal IMPROVED AXONAL CONDUCTION side of severed one-way tracts, and a smooth curving trajectory into their Eftekhar Eftekharpour(1), Soheila Karimi-Abdolrezaee(1,2,4), Jian Wang(1), distal pathway. Morphological correlates of axonal neoformation are being Hossam El Beheiry(1), Cindi Morshead(2,3) and Michael G. Fehlings sought to help identify healing after unmarked [recise lesions. (1,2,3,4). (1)Division of Cell and Molecular Biology, Toronto Western Research Institute, Krembil Neuroscience Center, Toronto, (2)Department of Surgery, (3)Institute of Medical Sciences, (4)Division of Neurosurgery, University of Toronto

Emerging evidence suggests that cell based remyelination strategies may be a feasible therapeutic approach for central nervous system (CNS) diseases characterized by myelin deficiency as a result of trauma, congenital anomalies or diseases. While experimental demyelination models targeted at the transient elimination of oligodendrocytes have suggested that

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88 B414 Eph family exert both unique and synergistic functional control on the CONTROL OF CNS CELL FATE DECISIONS BY SHP-2 AND ITS mammalian forebrain. (Supported by the Canadian Institutes for Health DYSREGULATION IN NOONAN SYNDROME Research, ALS, MDAC, NARSAD). Andrée S. Gauthier1,2,3, Olivia Furstoss1,2, Toshiyuki Araki5, Richard Chan5, Benjamin G. Neel5, David R. Kaplan2,3 and Freda D. Miller1,3,4. Developmental Biology1 and Cell Biology2 Programs, Hospital for Sick 90 B416 Children, Departments of Molecular and Medical Genetics3 and 'THE ROLE OF SRC-LIKE KINASES IN MYELINATION OF THE Physiology4, University of Toronto, and Department of Medicine5, Beth PERIPHERAL NERVOUS SYSTEM' Israel Deaconess Medical Center, Harvard Medical School S Hossain, G Fragoso, WE Mushynski and G Almazan. McGill University, Montreal Within the developing mammalian CNS, growth factors direct multipotent precursors to generate neurons or glial cells. We demonstrated Myelin is an insulating membranous structure surrounding axons, which that the growth factor-regulated protein tyrosine phosphatase SHP-2 is facilitates the saltatory conduction of action potentials. Deficiencies in essential for normal cortical cell fate determination, and that a mutation peripheral myelin result in neuropathies such as Charcot-Marie Toothe resulting in constitutive activation of SHP-2 in Noonan Syndrome, a human disease, warranting further studies into its underlying molecular mechanisms. syndrome associated with mental retardation and learning disabilities, causes Schwann cells (SC) synthesize myelin in the Peripheral Nervous System perturbations in this developmental process. Specifically, genetic knockdown (PNS). They provide trophic support to the axon, while axonal contact of SHP-2 in cultured cortical precursors or in in utero-electroporated influences SC growth, maturation and myelin synthesis. The molecular embryonic telencephalon inhibited basal neurogenesis and caused enhanced mechanisms by which PNS myelination occur have yet to be fully elucidated. and precocious astrocyte formation. Conversely, expression of an activated Fyn, a member of the Src family of cytoplasmic tyrosine kinases (SFK), SHP-2 mutant associated with Noonan Syndrome enhanced MEK-ERK plays a critical role in central nervous system myelination as suggested by the signaling to promote neurogenesis and negatively-regulated the gp130-JAK- reduced myelin content in brains of fyn-deficient mutant mice (Umemori et STAT pathway to inhibit gliogenesis. Neural cell fate decisions were al. 1994). Fyn transactivates MBP gene transcription (Umemori et al. 1999) similarly perturbed in the hippocampus and dorsal cortex of a mouse knock- and regulates OLG development in vitro (Osterhout et al. 1999). Fyn has in model that phenocopies human Noonan Syndrome. Thus, SHP-2 instructs been found in a protein complex associated with beta1 integrin/FAK and precursors to make neurons and not astrocytes during the neurogenic period, paxillin in differentiated dorsal root ganglion neurons and Schwann cell and perturbations in the relative ratios of these two cell types following cultures (DRGN-SC) (Chen et al, 2000). However a definitive function for constitutive SHP-2 activation may contribute to the cognitive impairments in Fyn or other Src family kinases in peripheral myelination had not been Noonan Syndrome patients. demonstrated. To assess whether SFK are involved in peripheral myelination, DRGN/SC cultures were treated with the SFK inhibitor PP2 at the initiation of myelination, started by ascorbate addition. PP2 caused a concentration- 89 B415 dependent decrease in MBP levels as assessed on day 10 by both Western UNIQUE AND SYNERGISTIC ROLES FOR EPHA4 AND B2 blot analysis and immunocytochemistry. PP2 and anti-fyn siRNA reduced the RECEPTORS IN COMMISSURAL DEVELOPMENT OF numbers of SCs expressing Krox-20, an inducible transcription factor MAMMALIAN FOREBRAIN required for peripheral myelination. Time-course experiments also revealed S.K.Y. Ho1, N. Kovacevic2, R.M. Henkelman3, A. Boyd4, T. Pawson5 and that PP2 had a significant effect on myelination even when cultures were Jeffrey T. Henderson1. 1Department of Pharmaceutical Sciences, Leslie treated several days after the initiation of myelination. MBP protein levels Dan Faculty of Pharmacy, University of Toronto, 2Baycrest Centre for were only partially recovered in a time-dependent manner following PP2 Geriatric Care, Rotman Research Institute, Toronto, 3Mouse Imaging removal. Thus, two clear phases of inhibition were evident. SFK inhibition Centre, Hospital for Sick Children, Toronto, 4Leukaemia Foundation caused a significant decrease in the length of myelinated segments following Research Unit, Queensland Institute of Medical Research, P.O. Royal quantification on immunofluorescent digital images of MBP Brisbane Hospital, Herston, Australia immunostaining. However, ultrastructural studies showed normal compaction of myelin. Similarly, the distribution of sodium channel, caspr Eph receptors represent the largest family of receptor tyrosine kinases and neurofilament expression as determined by immunofluorescence and have been shown to regulate a variety of cell-cell sorting decisions such appeared normal in PP2-treated cultures. Funded by the Multiple Sclerosis as neural crest cell migration, the formation of somatotopic maps, Society of Canada (MSSC) angiogenesis and axon guidance. Previous work from our laboratory has demonstrated that EphB2 is required for proper formation of the anterior commissure (AC). EphA4 has also suggested to be involved in the formation 91 B417 of the AC. However, the mechanism underlying these defects and potential DIFFERENTIAL REQUIREMENTS BETWEEN SKELETO-AND for redundancy with respect to EphB2/A4 signaling in the AC has not been FUSIMOTOR NEURONS FOR BCL-2 IN MEDIATING THEIR determined. In the present study, high-resolution magnetic resonance SURVIVAL DURING CNS DEVELOPMENT imaging (MRI) combined with in vivo retrograde labeling of CNS tracts was Hui, K.1, Kucera, J.2, J.T. Henderson1. 1Department of Pharmaceutical performed to determine the contribution of EphB2 and A4 receptors in Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, regulating the development of interhemispheric connections of the forebrain. 2Neurology Research, VA Medical Center, Boston, MA, USA Using single and combinatorial null mutants for each of these receptors, we have determined the unique and synergistic contributions of each. Our For the nervous system to self-assemble into a complex arrangement of findings demonstrate that EphB2 and A4 receptors exert distinct guidance synaptic connections, more neurons are produced during development than roles on the anterior and posterior branches of the AC. These studies further are ultimately incorporated into the network. This process is believed to show that these receptors also act synergistically to control aspect of AC involve competition among neurons for neurotrophic support supplied by guidance. While additional protein-protein interactions may play a role in their appropriate innervation targets. The process of programmed cell death regulating proper tract formation within mammalian forebrain, it is (PCD) has been implicated in promoting the demise of neurons that have interesting to note that we can experimentally recapitulate all of the major made improper connections. Members of the Bcl-2 protein family are interhemispheric guidance decisions in this region by proper expression of involved in the regulation of this process and represent a primary PCD EphB2 and A4. Taken together, these results demonstrate that members of the regulatory checkpoint within both developing and postnatal neurons.

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Previous analyses of bcl-2-/- mice have shown that despite the absence of 93 B419 any gross CNS abnormalities, some neuronal populations are more sensitive PHOSPHORYLATION AND CLEAVAGE OF PRESENILIN- to Bcl-2 deficiency, resulting in a subtle loss of neurons during and after ASSOCIATED RHOMBOID-LIKE PROTEIN (PARL) PROMOTES development. In the present study, we have analyzed in detail motor neurons CHANGES IN MITOCHONDRIAL MORPHOLOGY in the facial nucleus (branchiomotor neurons) and lumbar spinal cord Danny V. Jeyaraju*, Liqun Xu§, Marie-Claude Letellier*, Sirisha Bandaru*, (somatic motor neurons) of bcl-2-/- mice at postnatal day 30 to contrast any Rodolfo Zunino§, Eric A. Bergº, Heidi M. McBride§, and Luca Pellegrini*. differences between these two motor neuron subtypes in their dependencies *Centre de Recherche Université Laval Robert-Giffard, 2601 ch. de la for Bcl-2 for survival during development. Axonal counts and cross-sectional Canardière, Quebec City, QC, Canada G1J 2G3; §University of Ottawa area measurements along with motor neuron counts in the facial nucleus Heart Institute, 40 Ruskin Street, Ottawa; and º21st Century Biochemicals, revealed a significant loss of facial motor neurons in bcl-2-/- animals 33 Locke Drive, Marlboro, MA, USA compared to heterozygous controls. In addition, contrary to a previous report, it was determined that subpopulations of motor neurons in the facial nucleus Remodeling of mitochondria is a dynamic process coordinated by fusion do not exhibit differential sensitivity to Bcl-2 deficiency. In our examination and fission of the inner and outer membranes of the organelle, mediated by a of ventral roots at the level of the lumbar spinal cord (L4), reductions in axon set of conserved proteins. In metazoans, the molecular mechanism behind number and cross-sectional area were observed in Bcl-2 deficient mice. mitochondrial morphology has been recruited to govern novel functions, Interestingly, a shift in axon calibers seemed to have affected small caliber such as development, calcium signaling, and apoptosis, which suggests that axons preferentially while effects on large caliber axons appeared to be novel mechanisms should exist to regulate the conserved membrane minimal. By analyzing motor neuron populations in the lumbar spinal cord, fusion/fission machinery. Here we show that phosphorylation and cleavage we observed a corresponding loss of ChAT-positive motor neurons. The of the vertebrate-specific Pβ domain of the mammalian presenilin- selective loss of small caliber axons suggested that they were extended by associated rhomboid-like (PARL) protease can influence mitochondrial fusimotor neurons that normally innervate muscle spindles. Indeed, counts of morphology. Phosphorylation of three residues embedded in this domain, total fusimotor fibers within the soleus muscle indicated a significant Ser-65, Thr-69, and Ser-70, impair a cleavage at position Ser77–Ala78 that reduction in fusimotor innervation in bcl-2-/- mice. These findings indicate is required to initiate PARL-induced mitochondrial fragmentation. Our that fusimotor neurons are particularly sensitive to the loss of Bcl-2 and a findings reveal that PARL phosphorylation and cleavage impact majority of them die during development in its absence. mitochondrial dynamics, providing a blueprint to study the molecular evolution of mitochondrial morphology. 92 B418 OPTIMAL CA LEVELS REQUIRED FOR NEURITE OUTGROWTH 94 C401 IS REGULATED BY NCS-1 INTEGRATED DRUG DELIVERY IN CHITOSAN CHANNELS FOR Kwokyin Hui(1), Guang-He Fei(1), Bechara J. Saab(2,3), Jiang Su(1), John PROMOTING NEURAL STEM CELL DIFFERENTIATION C. Roder(2,3), Zhong-Ping Feng(1). Department of Physiology(1), and Howard Kim*, Charles Tator, Molly Shoichet. University of Toronto Molecular & Medical Genetics (2), Faculty of Medicine, University of Toronto; Mount Sinai Hospital(3), Toronto We are currently developing a strategy to induce regeneration of the spinal cord after injury by combining adult neural stem/progenitor cell Ca is an important regulator of neurite extension and growth cone (NSPC) transplants with a guidance channel implant. Earlier work has pathfinding. An optimal window level of Ca may be necessary for neurite demonstrated that we can achieve good survival of transplanted NSPCs, but outgrowth: lower levels stabilize growth cones and higher levels stall them, that almost half of these cells do not stain for markers of typical NSPC in both cases preventing extension. Cytosolic Ca can come from many lineages. We believe that providing the proper signals to the local sources, but how these are coordinated to reach and maintain the window environment will allow greater control over NSPC cell fate and result in level of Ca is unclear. Neuronal calcium sensor-1 (NCS-1) is a member of a increased therapeutic potential. It is our goal to incorporate drug-eluting superfamily of proteins that respond to local Ca changes. It interacts with polylactide-co-glycolide (PLGA) microspheres into these guidance channels various proteins involved in Ca homeostasis and is a likely candidate for to provide localized and sustained release of factors to influence cells present dynamically regulating cytosolic Ca levels. There is compelling evidence within the channels. Specifically, we aim to control NSPC cell fate in vitro that NCS-1 is involved in neurite development. However, no study has and in vivo through the delivery of phenotype-specific differentiation factors, examined how NCS-1 is involved in regulation of the window level of Ca resulting in enhanced populations of oligodendrocytes, astrocytes, and permissive to neurite outgrowth. In this study, we examined the effects of neurons. PLGA microspheres were prepared by a double emulsion method, NCS-1 on cytosolic Ca and neurite outgrowth in cultured L. stagnalis PeA with alkaline phosphatase used as a model protein. Encapsulation efficiencies neurons. Using RNA interference, we found that NCS-1 knockdown were consistently above 80% and average diameters can be varied from 15 to enhanced neurite extension and branching, and reduced activity-dependent 50 µm. To incorporate microspheres into the channel wall, microspheres Ca influx in growth cones. Using a C-terminal peptide of NCS-1, we found were suspended in a dilute buffered chitosan solution and spun-coated onto that the C-terminus modulates growth cone voltage-gated Ca currents, the interior of the chitosan channel. Alkaline phosphatase release was consistent with a previous finding. The peptide also affected neurite monitored over time in physiological conditions. Similar release profiles outgrowth and activity-dependent Ca influx. Interestingly, the C-terminal were observed from freely suspended microspheres and microspheres peptide had no effect on neurite extension as compared to the control, incorporated into the channels, with the protein remaining bioactive for the untreated neurons. Instead, it was more effective at enhancing neurite first two weeks. Thus, the embedded microsphere strategy appears to be branching and less effective at reducing activity-dependent Ca influx as feasible for the delivery of large molecules from the walls of chitosan compared to NCS-1 knockdown. Our findings indicate that NCS-1 channels. Several potential NSPC differentiation factors have been identified modulates neurite branching and extension by regulating Ca influx by at least including platelet-derived growth factor (PDGF) and bone morphogenic two mechanisms: one specifically affecting branching, and another affecting protein-2 (BMP2) for oligodendrocytes and astrocytes, respectively. By extension. Taken together, we propose that different regions of NCS-1 incorporating these factors into PLGA microspheres, we can characterize the regulate the cytosolic Ca concentration in growth cones in and out of the effectiveness of our system to deliver active signals to control NSPC cell fate optimal window level, consequently leading to changes in neurite outgrowth in vitro and eventually in an in vivo model of spinal cord injury. behaviors.

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95 C402 NPCs in the absence of neurons. Moreover, immunocytochemical staining MYOTOPIC ORGANIZATION OF LIMB INNERVATION BY for the cell surface marker PSA-NCAM showed abundant staining on SPINAL MOTOR NEURONS IS DEFINED BY NETRIN AND neuronal processes in co-cultured samples. Previous studies have shown that NETRIN RECEPTOR EXPRESSION PSA-NCAM expression by immature, unmyelinated axons is inversely Dayana Krawchuk*, Frederic Charron, Artur Kania. Institut de Recherches related to the gradient of myelination (Oumesmar et al., 1995; Charles et al., Cliniques de Montreal (IRCM), Montreal 2000), and that there is an upregulation of PSA-NCAM on neuronal fibres following demyelinating lesions (Charles et al., 2002; Oumesmar et al., A remarkable feature of the developing nervous system is the 1995). The high levels of PSA-NCAM expression on neuronal fibres in the establishment of topographical maps, wherein neuronal soma position is current study suggests that 1-week old cortical neurons inhibit myelin associated with the position of the innervation target. A simple and myotopic production by oligodendrocytes differentiated from adult spinal cord NPCs. topography is evident in the organization of the lateral motor column (LMC) Future work will examine the distribution of PSA-NCAM on neuronal spinal motor neurons and their axonal projections to limb muscles. Motor processes co-cultured for three weeks with spinal cord NPC derived neurons located in the lateral LMC innervate dorsal (extensor) limb muscles, oligodendrocytes, with particular emphasis on the relationship between whereas motor neurons located in the medial LMC innervate ventral (flexor) myelin production by oligodendrocytes and neuronal PSA-NCAM limb muscles. Limb mesenchyme axon trajectories of LMC neurons are expression. Our current results have important implications for the design of controlled by LIM homeodomain transcription factors expressed in the LMC future NPC transplantation trials, since they highlight the need to carefully motor neurons (Lim1 and Isl1) and limb mesenchyme (Lmx1b). These time the delivery of NPCs. transcription factors coordinately control the expression of Eph tyrosine kinase receptors and their Ephrin ligands, which are implicated in the specification of LMC axon trajectories. However, genetic evidence suggests 97 C404 the existence of additional effector molecules controlling LMC axon MCL-1 IS REQUIRED FOR NEURONAL SURVIVAL guidance in the limb. To uncover new LMC axon guidance determinants, we J. N. LeGrand* (1), J. Vanderluit (1), N. Arbour (1), E. Cheung (1), J.T. carried out a screen for molecules whose expression is restricted to the dorsal Opferman (2), D. Park (1), R. Slack (1). 1. University of Ottawa, Ottawa or ventral limb mesenchyme at the time of choice of dorsal or ventral axon Health Research Institute, Department of Cellular and Molecular Medicine/ trajectory. We found that Netrin1, a gene encoding a diffusible molecule Neuroscience, Ottawa, 2. Department of Biochemistry, St. Jude Children's required for attractive or repulsive guidance of many classes of axons, is Research Hospital, Memphis, USA expressed specifically in the dorsal limb mesenchyme and is under the control of Lmx1b. Our analysis of Netrin receptor mRNA distribution Unregulated neuronal cell death has been implicated in the pathogenesis demonstrates that receptors associated with attraction towards Netrin are of several neurological disorders and in acute neuronal injury such as stroke. expressed by lateral LMC motor neurons innervating the dorsal limb, and The Bcl-2 family of proteins plays an integral role in the regulation of receptors associated with repulsion from Netrin are expressed by medial apoptotic cell death. Mcl-1, an anti-apoptotic member of the Bcl-2 family; is LMC motor neurons innervating the ventral limb. This restricted Netrin a known survival factor for hematopoietic cells. Little is known, however, receptor expression leads to our hypothesis that Netrin1 is a bifunctional regarding its function in the nervous system. The embryonic lethality of motor axon guidance cue in the limb mesenchyme that attracts lateral LMC germline Mcl-1 knockout mice at E3.5 has hindered detailed examination of axons to the dorsal limb and repels medial LMC axons towards the ventral its role in the nervous system. To examine the role of Mcl-1 in nervous limb, thus controlling LMC myotopy. We are currently testing this system development, we used conditional knockouts of Mcl-1 by crossing hypothesis through gain and loss of function of Netrin pathway components Mcl-1-floxed mice with mice expressing Cre from the Nestin, Foxg1 or in both the mouse and the chick. CamKIIα promoter. Deletion of Mcl-1 during nervous system development with either Nestin or Foxg1 Cre resulted in embryonic lethality. Morphological analysis using Cresyl Violet staining revealed severe 96 C403 deterioration of the cortices of both conditional knockouts, demonstrating NEURONAL CO-CULTURE INHIBITS MYELIN PRODUCTION BY that Mcl-1 is required for embryonic neuronal survival. OLIGODENDROCYTES FROM DIFFERENTIATED ADULT RAT Immunohistochemical staining of brain sections with antibodies to active SPINAL CORD NEURAL PRECURSOR CELLS caspase-3 (AC3) revealed numerous apoptotic cells throughout the *Kulbatski, I., Logan, R., and Tator, C.H. Institute of Medical Science, developing ventricular zone at E12.5 and E15.5. Double staining of AC3 with University of Toronto, and Toronto Western Research Institute, University Nestin or Tuj revealed neurons are dying throughout the process of Health Network, Toronto differentiation. Proliferation was assessed via phosphohistone-H3 staining and found to be comparable in the knockouts and controls, indicating that cell We recently showed that adult rat spinal cord derived neural precursor proliferation was not affected. Deletion of Mcl-1 in post mitotic neurons in cells (NPCs) differentiate primarily into myelin producing oligodendrocytes postnatal mice with CamKIIα Cre also resulted in premature lethality in vitro, making them appropriate candidates for future spinal cord injury at 1 and 2 months of age. Cresyl Violet staining and NeuN immuno- (SCI) transplantation trials since they have the potential to remyelinate histochemistry revealed a rapid loss of neurons in the cortices of the demyelinated or regrowing axons (Kulbatski et al., 2007). Purpose: In the conditional knockouts. A lack of apoptotic markers in the knockout brains current study, we tested the in vitro ability of adult rat spinal cord NPCs to suggested a form of cell death distinct from apoptosis. Electron myelinate cortical neurons, as a measure of their functional capacity. micrographic imaging revealed double membraned vesicles within the Hypothesis: We hypothesized that adult rat spinal cord NPCs will produce cortical neurons, suggestive of an autophagic form of cell death. Altogether functional oligodendrocytes that myelinate co-cultured rat cortical neurons. our findings demonstrate that the loss of Mcl-1 in embryonic and post- NPCs were isolated and grown from adult Wistar rats as described previously mitotic neurons results in cell death. The two distinct forms of cell death (Kulbatski et al., 2007). NPCs were differentiated on Matrigel for 1 week, activated indicate that Mcl-1 functions in multiple pathways to promote after which freshly isolated neonatal cortical neurons were added for an neuronal survival. In summary, we demonstrate that Mcl-1 is vital for the additional week. Parallel samples were prepared for transmission electron survival of neurons. Funded by Heart and Stroke Foundation. microscopy (TEM) and immunocytochemical analyses. Although double labelling immunocytochemistry showed close association of RIP+/MBP+ oligodendrocytes with MAP2+ neurons, TEM analysis showed the complete absence of myelin profiles compared with control cultures of differentiated

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98 C405 100 C407 SEMAPHORIN 5B IS A REPELLANT CUE FOR THE DEVELOPMENTAL EXPRESSION OF A NOVEL CORTICOTHALAMIC PROJECTION PHILANTHOTOXIN-INSENSITIVE CA2+-PERMEABLE AMPA R.L.M. Lett, T.P. O'Connor. Programme in Neurosciences, Department of RECEPTOR IN THE MAMMALIAN RETINA Cellular and Physiological Sciences, Faculty of Medicine, University of Ingrid Osswald, Alba Galan, Derek Bowie. Department of Pharmacology & British Columbia Therapeutics, McGill University, Montreal, Quebec

Neuronal connectivity is generated by the precise guidance of neuronal Ca2+-permeable AMPA receptors (AMPARs) are expressed throughout growth cones in response to the spatiotemporal distribution of molecular the adult CNS but yet their role in development is poorly understood. In the guidance cues in the developing embryo. Connections between cortex and developing retina, early Ca2+ oscillations in retinal ganglion cells are later thalamus are among the longest and most complex projections of the replaced by light-induced activity mediated by NMDA receptors mammalian forebrain, requiring many intermediate targets and guidance (NMDARs). However, NMDARs are absent from many retinal cells, decisions. Although some cues are known for their roles, there remains some suggesting that other Ca2+-permeable glutamate receptors may be important question as to the full complement of guidance cues necessary for the to consider. Here, we used cobalt staining to label selectively retinal cells that formation of this tract. We have found that the class 5 semaphorin, Sema5B, express Ca2+-permeable AMPARs. In addition, we made electro- is expressed at important histogenic boundaries and regions of the subcortex physiological recordings of spontaneous synaptic activity in single retinal flanking the internal capsule during corticothalamic axon guidance. Explants cells to reveal their functional properties. Specifically, we used of dorsal and lateral cortex grown in culture exhibited a characteristic philanthotoxin (PhTX), a synthetic polyamine previously shown to block avoidance behavior and growth cone collapse upon contact with Sema5B selectively Ca2+-permeable receptors in other brain regions. We found that expressing cells, suggesting Sema5B may function as a repulsive guidance inhibitory horizontal and AII amacrine cells devoid of NMDARs expressed cue. To further test this, Sema5B expressing cells were transplanted into Ca2+-permeable AMPARs at all stages of development. Prior to eye- organotypic slices along the presumptive internal capsule and ganglionic opening, Ca2+-permeable AMPARs were fully blocked by PhTX; however, eminences. Ectopic Sema5B was sufficient to cause cortical axons to avoid cobalt staining in inhibitory cells persisted in the presence of PhTX after eye- their normal trajectory, resulting in either stalling at the boundary of Sema5B opening. Moreover, Joro spider toxin and IEM-1460 also failed to cells or turning into inappropriate areas of the cortex. We therefore propose antagonize, demonstrating that this novel pharmacology is shared by several that Sema5B may be an important guidance component for establishment of AMPARs blockers. Electrophysiology confirmed that AII amacrine cells the corticothalamic tract. displayed synaptic activity insensitive to PhTX after eye-opening. Taken together, we show that expression of Ca2+-permeable AMPARs is developmentally regulated in the mammalian retina. Surprisingly, Ca2+- 99 C406 permeable AMPARs displayed a phenotype switch in PhTX-sensitivity that DEAD BOX PROTEINS ARE COMPONENTS OF DISTINCT coincides with the establishment of inhibitory cell connections. We speculate POPULATIONS OF RNA GRANULES that PhTX-insensitive Ca2+-permeable AMPARs may be critical for synapse Miller LC(1), Badeaux F(2), DesGroseillers L(2), Sossin WS(1). 1. McGill maturation in the mammalian retina. University, Montreal, Quebec, Canada 2. University of Montreal, Montreal

Localized protein synthesis is required for many processes from axon 101 C408 development to learning and memory formation. Transport of the mRNAs to TRK SIGNALING REGULATES NEURAL PRECURSOR CELL sites of local synthesis is mediated through particles called RNA granules. PROLIFERATION AND DIFFERENTIATION DURING CORTICAL The components of these granules are involved in mediating transport and DEVELOPMENT regulating the translational competence of the mRNAs. A proteomics K. Bartkowska, A. Paquin, A.S. Gauthier, D.R. Kaplan, F.D. Miller. analysis of a heterogenous collection of RNA granules isolated from E18 rats Developmental and Stem Cell Biology, and Cell Biology, Hospital for Sick has identified many of the proteins involved. Among the proteins identified Children, Departments of Molecular and Medical Genetics, Physiology, and are members of the DEAD box (DDX) RNA helicase family – including Institute of Medical Science, University of Toronto, MaRS Discovery District, DDX 1, DDX 3, DDX 5 (p68), and DDX 6 (RCK/p54) (Elvira et al., Mol Toronto Cell Proteomics, 5(4) 635, 2006). Characterization of these proteins in cultures of early embryonic hippocampal neurons, through both The neurotrophin family of growth factors is known to be essential for overexpression of fusion proteins and endogenous staining, has revealed a CNS neurons, but is not thought to regulate the function of multipotent CNS punctate distribution of all four DDX proteins in both axons and dendrites. neural precursors. Here, we have asked whether neurotrophin-mediated Trk Localization studies of the overexpressed DDX proteins indicate that DDX 1 signaling is important for embryonic cortical precursor cell development by and DDX 3 are mostly localized to distinct puncta while DDX 5 and DDX 6 genetically manipulating cultured cortical precursors, and by performing in colocalize with DDX 3 more than with DDX 1. Nevertheless, DDX 1 utero electroporation with dominant-negative TrkB and TrkC to acutely, and colocalizes strongly with CGI99, a novel protein identified in the proteomics. in a cell-autonomous fashion, disrupt Trk signaling in the embryonic cortex. This is in agreement with the CGI99:DDX 1 interaction observed by Kanai These experiments demonstrated that TrkB and TrkC signaling was essential et al. (Neuron, 43(4) 514, 2004). As all the proteins were identified in the for the proliferation of embryonic cortical precursors, both in culture and in purified granules this indicates that there are multiple types of granules with vivo. Moreover, inhibition of TrkB and TrkC signaling in embryonic cortical distinct DEAD box protein compositions. Interestingly, DDX1 and DDX3 precursors in vivo led to a delay in the generation of new neurons, and show a greater colocalization in axons versus dendrites, while there is no ultimately perturbed the postnatal localization of cortical neurons. In change in the colocalization with CGI99 in either case. Further, contrast, TrkB and TrkC receptor signaling was not required for cortical DDX1:DDX3 puncta in axons are more likely to contain P0 – a marker for astrocyte formation, at least within the first few days postnatally. Instead, large ribosomal subunits – than DDX1 puncta alone. The yeast homolog of inhibition of Trk signaling in embryonic cortical precursors led to a decrease DDX 6, Dhh1p, is a marker for processing (P) bodies - RNP particles in the proportion of postnatal cortical precursors that were maintained within involved in decapping and degradation of mRNAs. However, other P body the subventricular zone, possibly as a direct consequence of the decrease in components were not identified in the proteomics analysis and they do not embryonic proliferation. Together, these results indicate that TrkB and TrkC show strong colocalization with other RNA granule components. In activation regulate the proliferation and differentiation of embryonic cortical conclusion, distinct types of RNA granules are involved in the transport and precursors, suggesting that TrkB and TrkC ligands such as BDNF and NT-3 translational regulation of mRNAs in developing neurons. control cortical development at earlier stages than previously thought.

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102 C409 104 C411 ADULT NEURAL STEM CELLS ARE COMPETENT TO RESPOND NOVEL GENE TARGETS FOR MELATONIN IN A NEURAL STEM TO ENDOGENOUS FACTORS DERIVED FROM THE CELL LINE EMBRYONIC FOREBRAIN Rohita Sharma*, L.P. Niles. Department of Psychiatry and Behavioural N. Sachewsky*, V. Cheng, A. Kam, J. Young and CM Morshead. University Neurosciences, McMaster University, Hamilton of Toronto, Department of Physiology, Department of Surgery, T. Donnelly Centre for Cellular and Biomolecular Research Several stem cell lines have been utilized to replace cell loss in models of . neurodegeneration, including those for Parkinson’s disease (PD). However, The periventricular region of the mammalian brain contains a population of the assessment of transplanted stem cells has indicated that only 0.13-0.35% neural stem cells (NSCs) that is maintained into adulthood. Individual of transplanted cells acquire a dopaminergic phenotype in animal models of AdNSCs and ENSCs proliferate to generate clonally derived colonies of cells PD, as determined by tyrosine hydroxylase (TH). Therefore, it is of interest termed “neurospheres” in the presence of growth factors. ENSCs and to characterize the factors that are necessary for survival and differentiation AdNSCs differ in their non-cell autonomous response to cell density in vitro. of precursor stem cells in order to improve the success rate of stem cell We asked if the factors responsible for the exponential increase in embryonic therapy. The pineal gland hormone melatonin has been implicated as having neurosphere formation can modify the linear increase in adult neurosphere a role in neuronal survival and differentiation. Moreover, chronic treatment formation to determine if AdNSCs and ENSCs were inherently different or if with a physiological dose of this lipophilic hormone protects the nigrostriatal their differential responsiveness was due to the lack of permissive or pathway in 6-hydroxydopamine-lesioned rats, as reflected by behavioural presence of an inhibitory factor. We performed mixing experiments with and immunohistochemical (TH) analyses (Sharma et al., 2006). Previous tissue isolated from AdYFP expressing mice and E14/15 CD1 embryos and studies in our laboratory, using the mouse neonate cerebellum-derived C17.2 found that numbers of Ad neurospheres was significantly increased in stem cell line, indicated that these cells express the melatonin MT1 receptor primary co-cultures with E cells. Delayed mixing of cells by 2 days did not subtype. In addition, melatonin treatment of C17.2 cells significantly induced mimic this increase suggesting the effect was on AdNSC survival. the mRNA expression of glial cell-line derived neurotrophic factor (GDNF), Conditioned media from primary E cultures resulted in the same increase in which is known to play an essential role in dopaminergic cell survival (Niles neurosphere formation from both Ad primary and Ad secondary (passaged) et al., 2004). Given that melatonin enhances neuronal differentiation and neurospheres. The effect on AdNSCs can be seen in co-cultures of adult and GDNF expression, we hypothesized that it would also modulate the NSCs from animals as early as E12.5 and as late as postnatal day 5 but is lost expression of genes that are integral to such differentiation and specifically at later times. Since the effect cannot be mimicked using pure populations of to the development of a neuronal phenotype. In the current study, cultured neurosphere derived stem and progenitor cells, we hypothesize that the C17.2 cells were exposed to physiological doses of melatonin (picomolar to factor(s) is released from cells present within primary dissected tissue such nanomolar range) for 24 hours. RT-PCR studies revealed a significant dose- as neurons or endothelial cells (and not glial cells since they are not present dependent increase in Nurr1 mRNA expression after melatonin treatment. at E12.5). We are testing candidate molecules as well as using conditioned The orphan nuclear receptor Nurr1 is a transcription factor that has been media from pure populations of candidate cells. Taken together, these data shown to be pivotal for the development and maintenance of dopaminergic suggest that temporally distinct populations of NSCs are not inherently neurons. Furthermore, increased mRNA expression of the early neuronal different and that AdNSCs maintain their competence to respond to E tissue marker, beta-III-tubulin, was also observed following in vitro treatment. derived cell survival factors. Finally, melatonin treatment modulated the mRNA expression of several histone deacetylases (HDACs). This family of transcriptional repressors is implicated in development and cellular differentiation. These findings 103 C410 suggest that melatonin plays a role in neuronal differentiation to a A POTENTIAL ROLE FOR THE CYTOSKELETAL LINKER dopaminergic phenotype, possibly by modulating epigenetic targets in the PROTEIN, MOESIN, IN DROSOPHILA NEUROMUSCULAR C17.2 stem cell line. JUNCTION MORPHOLOGY Seabrooke, S*. and Stewart, B. Department of Biology, University of Toronto at Mississauga, Mississauga 105 C412 THE ROLE OF LONG-TERM IMMUNE DYSFUNCTION IN Although it is known that actin plays a role in synaptic development, the ADULT-NEUROGENESIS precise role of actin and actin-binding proteins remains unknown. Moesin is Michelle M. Sidor, Patrick J. Martin, Glenda MacQueen, & Jane A. Foster. a member of the ERM family, which link F-actin to the plasma membrane. Department of Psychiatry & Behavioural Neurosciences, McMaster Moesin is the only ERM homolog present in Drosophila providing a University; Brain-Body Institute, St. Joseph’s Healthcare, Hamilton unique opportunity to gain an understanding of the role of ERM proteins in actin dynamics. In the neuromuscular junction (NMJ), overexpression of Events occurring during the early neonatal period can have significant Moesin was able to rescue the morphology of NSF2-induced NMJ long-term consequences on a variety of behavioural and physiological overgrowth. This NSF mutant is known to have reduced synaptic strength systems. For instance, rodents neonatally exposed to an early immune and reduced F-actin in the nerve terminal. To further investigate the potential challenge with the bacterial product lipopolysaccharide (LPS) exhibit role of Moesin in NMJ development, immunocytochemical quantification of increased anxiety-like behaviour, cognitive deficits, greater stress-reactivity, NMJ branch length was completed for gain-of-function and loss-of-function and altered neuroimmune responses in adulthood. This is fascinating in the moesin in conjunction with the overgrown phenotype. Loss-of- context that all of the above perturbations are observed in the clinically function moesin enhanced the NMJ overgrowth indicating a likely depressed population. Studies to date, however, have yet to examine role for Moesin in normal NMJ development. However, using depressive-like phenotypes in early immune challenged rodents. Given that electrophysiology it was determined that while overexpression of Moesin deficits in neurogenesis are hypothesized to be a contributing factor in the rescues the morphology, there was not a corresponding rescue of synaptic etiology of depression, the present study examines adult neurogenesis and strength in the NSF2 mutant. Together this implies a role for moesin at the depressive-like behaviour in early immune challenged mice. Mice were NMJ as well as implying the possibility that there are distinct mechanisms injected with LPS (0.05 mg/kg) on postnatal days three and five. Depressive- involved with the morphology and physiology of the Drosophila like behaviour was assessed using the forced swim test (FST) at twelve NMJ. weeks of age. Four days after the FST, mice were given pulse injections of BrdU (50mg/kg) in order to assess hippocampal neurogenesis. Preliminary

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analysis of the FST data has yielded a surprising result: a decreased amount TrkA, the receptor tyrosine kinase for nerve growth factor (NGF), is of immobility during the FST in LPS injected mice compared with controls. critical not only for the correct spatial and temporal development of sensory This finding may reflect an increased level of anxiety-like behaviour as has neurons during embryogenesis but also for the survival of sensory neurons, been reported previously. Immunohistochemical analysis of neurogeneic the differentiation and apoptosis of neuronal tumours and suppression of markers (BrdU & doublecortin) is currently being performed to assess latent herpes simplex virus (HSV) genomes. The transcription factor Brn3a hippocampal neurogenesis in early immune challenged mice. Successful is known to play an important role as an enhancer of TrkA transcription completion of this work will help to reveal the contribution of the early during development. Despite considerable information on the embryonic immune environment to long-term alterations in neurogenesis and to the later regulation of TrkA, the mechanisms by which the expression of TrkA is development of neuropsychiatric disorders. regulated in differentiated neurons, or the factors that influence its expression in tumour cells, have not been identified. By examining a segment of DNA that lies upstream from the coding sequences of human TrkA, we have 106 C413 identified two regions within 190 base pairs of the TrkA reading frame that THE P75 NEUROTROPHIN RECEPTOR MEDIATES AXON bind recombinant Brn3a. This segment of the TrkA promoter is also DEGENERATION TO REGULATE SYMPATHETIC AXON sufficient to initiate transcription in PC12 cells, a model of rat sympathetic PRUNING neurons, and in medulloblastoma cells. By introducing an active gene for *Karun K. Singh1,3,4, Bianca M.R. Kramer3,4, Elizabeth J. Hong6, Mike E. Brn3a into cells we also show that the protein can enhance the expression of Greenberg6, David. R. Kaplan2,3,5, and Freda D. Miller1,2,3,4,5. the endogenous TrkA. Since the expression of TrkA is required for the 1Institute of Medical Science and 2Department of Molecular and Medical differentiation or apoptosis of medulloblastoma cells, our work may lead to Genetics, University of Toronto, and 3Developmental Biology, 4Brain and strategies for treating this often-fatal childhood tumour. Behaviour, and 5Cancer Research Programs, Hospital for Sick Children, Toronto, 6Neurobiology Program, Children's Hospital Boston, Harvard Medical School, Boston, Massachusetts, USA 108 C415 EFFECT OF INDUCIBLE EXPRESSION OF HOXA2 GENE ON One strategy used by the developing mammalian nervous system to THE PROLIFERATION AND DIFFERENTIATION OF THE RAT establish neural circuitry is the overproduction of axons and the subsequent CG4 OLIGODENDROGLIAL CELLS selection of only those axons which successfully compete for target Monica Wang1, J. Ronald Doucette2, Adil J. Nazarali1. Laboratory of innervation. The elimination of axons is termed “axon pruning”, and occurs Molecular Biology, College of Pharmacy and Nutrition1, University of in many CNS and PNS neuronal populations. In this study, we have focused Saskatchewan, Saskatoon and Department of Anatomy and Cell Biology, on peripheral sympathetic neurons to study axon competition and pruning, College of Medicine2, University of Saskatchewan, Saskatoon where target-derived Nerve Growth Factor (NGF) and neural circuit activity regulate pruning during development. Using an in vitro model of axon Oligodendrocytes (OLs) are the glial cells responsible for the synthesis competition, our previous study demonstrated that in the presence of NGF, and maintenance of myelin in the central nervous system. Recently, Hoxa2 local depolarization conferred a competitive growth advantage to stimulated was found by our laboratory to be expressed by OLs and down-regulated at sympathetic axons, while it disadvantaged the growth of unstimulated axons the terminal differentiation stage during oligodendrogenesis in mice (Nicolay deriving from the same and neighboring neurons. In addition, we found the et al., 2004). To further investigate the role of Hoxa2 in oligodendroglial growth disadvantage was mediated by BDNF secreted from and acting on the development, a tetracycline regulated controllable expression system was unstimulated axons through p75NTR. In this study, we directly tested utilized to establish two stable cell lines where the expression level of Hoxa2 whether BDNF or p75NTR plays a role in sympathetic axon pruning in vivo. gene could be up-regulated (CG4-SHoxa2) or down-regulated (CG4- Using an in vivo model, we found that pruning of p75NTR -/- sympathetic ASHoxa2). Morphologically, no obvious differences were observed between eye-projecting axons was completely inhibited compared to WT controls. In CG4-SHoxa2 and CG4 wild type cells, whereas CG4-ASHoxa2 cells addition, preliminary studies suggest that sympathetic axon pruning is also exhibited much shorter processes. Data from BrdU uptake assays indicated perturbed in mice lacking the activity dependent promoter element of the that an up-regulation of Hoxa2 gene promotes the proliferation of CG4- BDNF gene, indicating activity dependent BDNF synthesis may be required SHoxa2 cells. Transcription of PDGFR, a receptor for the mitogen for pruning. We also utilized compartmented cultures to determine the role of PDGF and which enhances the survival and proliferation of OLs, was p75NTR in sympathetic axon competition and pruning. Here we found that assessed to examine whether Hoxa2 promotes CG4-SHoxa2 cell the growth disadvantage of WT unstimulated axons was completely proliferation via increasing the mRNA level of PDGFR. In eliminated in p75NTR -/- unstimulated axons. Furthermore, the growth addition, specific investigations of the differentiation of CG4-SHoxa2 cells disadvantage was due to p75NTR-mediated axon degeneration of were carried out by characterizing the composition of stage specific unstimulated axons. Interestingly, immunocytochemistry revealed BDNF, oligodendroglial subpopulations in culture. Our immunocytochemical study p75NTR and Ubiquitin were enriched in degenerating beads along individual did not indicate the differentiation course of the genetically engineered cells unstimulated axons, suggesting localized BDNF-p75NTR signaling induces was significantly altered compared to CG4 wild type cells, although results axon degeneration. Finally, our biochemical data demonstrate that p75NTR from semi-quantitative RT-PCR of oligodendrocyte-specific ceramide mediates these effects in part by dampening NGF-induced MAPK signaling, galactosyltransferase (CGT) and myelin basic protein (MBP) provide and by activating a Rho-ROCK pathway. Taken together, our data convincing evidence that the differentiation of CG4-SHoxa2 cells was demonstrate BDNF-p75NTR signaling regulates sympathetic axon pruning delayed when Hoxa2 gene was up-regulated. (Supported by CIHR) by inducing axon degeneration.

109 C416 107 C414 THE ROLE OF FOXP2 IN CORTICAL DEVELOPMENT NOVEL BRN3A CIS-ACTING SEQUENCES THAT MEDIATE Weaver I.C.G., Kaplan D.R., & Miller F.D. Developmental & Stem Cell ACTIVATION OF THE NERVE GROWTH FACTOR RECEPTOR, Biology, Cell Biology, Hospital for Sick Children, Departments of Molecular TRKA, IN NEURONS & Medical Genetics, Physiology, Institute of Medical Science, University of Ximena Valderrama and Vikram Misra. Department of Veterinary Toronto, Medical & Related Sciences (MaRS) Centre, Toronto Microbiology, Western College of Veterinary Medice, University of Saskatwan, Saskatoon The FOXP2 gene, which is essential for the normal development of speech and language, encodes a zinc-finger transcription factor that is

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expressed in developing neural structures, including newly-born cortical demonstrate that p73+/- mice undergo age-dependent neurodegeneration, neurons (Ferland et al., JCN, 2003). Recent genetic evidence shows that the indicating that p73 is essential in maintaining neuronal survival throughout FOXP2 gene is associated with susceptibility to autism (Feuk et al., AJHG, the lifetime of an organism, and suggest that humans with perturbations in 2006). Since disruption of FOXP2 impairs speech and motor functions, p73 levels may show an enhanced propensity for neurodegeneration. inhibits ultrasonic vocalization in mouse pups, and in an as-yet-undefined Supported by CIHR, NeuroScience Canada, Postdoctoral Fellowship from manner perturbs the early development of at least some CNS neurons (Shu et CIHR/ Heart and Stroke Foundation of Canada al., PNAS, 2005), we propose that FOXP2 is essential for the normal genesis and maturation of cortical neurons, and that such cortical perturbations underly the observed behavioral deficit in vocalization. Cortical development 111 C418 is a complex process in which extrinsic and intrinsic factors modulate the IMPACT OF INTERLEUKIN-1β, TUMOR NECROSIS sequential generation of neurons and glial cells. The Miller/Kaplan FACTOR-α, AND INTERLEUKIN-6 ON HIPPOCAMPAL laboratory has developed cultures of embryonic murine cortical precursors CELLULAR PROLIFERATION that undergo this same sequence of development in culture. Using these Brennan, J.P.*, Seguin, J.A., Mangano, E.N., Mott, G.N., Litteljohn, D. & cultures, we performed a developmental time-line to determine the Hayley, S. P, Institute of Neuroscience, Department of Psychology, Carleton expression of FOXP2 in developing cortical precursors and neurons and University tested the effects of FOXP2 overexpression and FOXP2 shRNA expression in the newly-born neurons. To determine whether these findings were Accumulating evidence indicates that alterations of hippocampal relevant in vivo, we utilized the same constructs to perturb FOXP2 functioning may influence affective state and cognition. Specifically, expression in cortical precursors and/or newly-born cortical neurons in vivo. disturbances of hippocampal plasticity such as impaired dendritic branching Specifically, immnohistochemical staining reveals that FOXP2 is expressed and neurogenesis have been implicated in depressive behavior. Several in newly-born neurons of the cortical plate and the striatum, which co- reports suggest that various signalling messengers, including growth factors express GAD65/67. Therefore, we performed in utero electroporation to and cytokines, might be involved, particularly proinflammatory cytokines tested the effects of ectopic FOXP2 expression in the cortical precursors and which have been found to have potent effects upon several processes linked FOXP2 shRNA expression in newly-born neurons of the striatum, and then to depression including both central monoamine and neuropeptide activity. analyzed survival, migration and differentiation of the genetically- Recently, administration of the immunotherapeutic cytokine, interferon- manipulated cells at various time points following electroporation. γ was reported to diminish hippocampal neurogenesis and provoke Understanding of the nature of FOXP2 involvement in cortical behavioural signs of depression. Therefore, we assessed whether 3 additional development serves as an important bridge between research on molecular proinflammatory cytokines (which may be altered in depressed individuals) genetics, neuronal development and behavior. The question then is whether influenced hippocampal cellular proliferation (neurogenesis and the differential proliferation of these precursor cells might directly alter the gliogenesis). Acute systemic administration of tumor necrosis factor-α development and function of neuroendocrine systems that regulate behavior (TNF-α) reduced hippocampal cell proliferation and decreased in mammals later in life. References: Barnabe-Heider, F. et al., Neuron dendritic branching, yet, interleukin-1β (IL-1β) and IL-6 had no (2005) 48, 253-265.; Ferland, R.J. et al., J. Comp. Neurol. (2003) 460, 266- significant effects. However, chronic but not acute infusion of IL-6 and IL- 279.; Shu, W. et al., Proc. Natl. Acad. Sci. (2005) 102, 9643-9648.; Feuk, L. 1β into the hippocampus increased cellular proliferation but TNF- et al., Am. J. Hum. Genet. (2006) 79, 965-72. α had no effect in this respect. Thus, the route and chronicity of cytokine administration had a marked influence upon the nature of the alterations of cellular proliferation. These results are discussed in terms of 110 C417 potential mechanisms of cytokine action and functional implications. A ROLE FOR THE P53 FAMILY MEMBER, P73, IN AGE-RELATED NEURODEGENERATION Wetzel, MK, Cole, CJ, Josselyn, SA, Frankland, PW, Kaplan, DR, and Miller, 112 C419 FD. Departments of Stem Cell and Developmental Biology, Cell Biology, ELECTRICAL STIMULATION OF INTACT PERIPHERAL AXONS and, Brain and Behavior, The Hospital for Sick Children, Toronto; FROM SENSORY NEURONS IN RATE PROMOTES OUTGROWTH Departments of Physiology and Medical Genetics, University of Toronto OF THEIR CENTRAL PROJECTIONS Esther Udina (1), Matt Furey (1), Sarah Busch (2), Jerry Silver (2), Karim A central question in neurobiology is how terminally differentiated post- Fouad (1) and Tessa Gordon (1). (1) Center for Neurosciences, University of mitotic neurons generated during embryonic development survive Alberta, Edmonton, Alberta, Canada T6G 2S2, 2Case Western Reserve throughout the duration of an organism’s lifetime. Neuronal life versus death University School of Medicine, Department of Neurosciences, 2109 Adelbert is controlled in part by a novel cell survival checkpoint comprised of p53 Road E-658, Cleveland, Ohio 44106, USA family members. p53 and p63 work in concert to promote neuronal death, whereas, a shortened, dominant inhibitory form of p73, ΔNp73, Electrical nerve stimulation (ES) promotes axonal outgrowth after mediates survival. ΔNp73, the predominantly expressed isoform in the peripheral nerve injury in contrast to a conditioning lesion (CL) of a nerve nervous system, is a key survival factor required for the survival of several that promotes outgrowth and accelerates rate of axonal regeneration developing neuron populations, and vulnerability of adult neurons to injury- following a second injury. A CL also promotes regeneration of the central induced death. The extent of p73’s involvement in ensuring long-term axon of dorsal root ganglia (DRG) sensory neurons across a spinal cord neuronal survival has yet to be explored. Here we investigate the role of p73 lesion site. We asked whether ES of the intact sciatic nerve promotes in age-related neurodegeneration by examining both behaviorally and outgrowth of cut central DRG axons. The sciatic nerve of adult rats was anatomically young (3 month) and old (16 month) mice which were lacking stimulated at 20Hz, 7 days before harvest and primary culture of the DRG a single allele of p73. The behavioral analysis revealed that aged, but not neurons on a permissive growth substrate. ES increased neurite outgrowth 4- young, p73+/- mice displayed a phenotype characteristic of mice with fold as compared to non-stimulated DRG neurons. In vivo, we transected the neurodegeneration; they exhibited a defective limb clasping reflex, decreased dorsal columns at T8 in the spinal cord and, the sciatic nerve was either cut grip strength, and reduced anxiety. Moreover, investigation of gross brain (CL), electrically stimulated (ES) for 1h at 20Hz or 200Hz. The control anatomy demonstrated that whereas the brains of young p73+/- mice were group had Sham sciatic nerve surgery. After 14 weeks, ES at 20Hz but not virtually indistinguishable from their wild-type counterparts, the aged p73+/- 200Hz significantly increased axon outgrowth into the lesion site but not mice displayed an obvious cerebral cortical atrophy. This atrophy was due to axon regeneration as compared to the Sham control. The CL did not affect both decreased cortical thickness and neuronal loss or atrophy. These data

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axon outgrowth but significantly increased the number and distance of 116 A104 regenerating axons in the lesion site. We only found significant increase in GALANTAMINE: A NOVEL NEUROPROTECTANT FOR INJURED cAMP for the 20Hz but not the 200Hz ES or the CL. We conclude that the RETINAL GANGLION CELLS IN GLAUCOMA effect of ES in promoting axonal outgrowth may be attributed to increased Mohammadali Almasieh*1, Yu Zhou1 and Adriana Di Polo1,2. intracellular levels of cAMP in contrast to the effect of the CL of increasing 1Department of Pathology and Cell Biology & 2Department of the rate of regeneration that was not (Funded by CIHR to TG and NIH to JS). Ophthalmology, University of Montreal

Glaucoma, the second leading cause of blindness worldwide, is 113 A101 characterized by progressive optic nerve degeneration that leads to WILD-TYPE SUPEROXIDE DISMUTASE ACQUIRES BINDING irreversible visual field loss. A hallmark of glaucoma is the death of retinal AND TOXIC PROPERTIES OF ALS-LINKED MUTANT FORMS ganglion cells (RGCs). A major risk factor for developing this disease is THROUGH OXIDATION elevated intraocular pressure (IOP). The current standard therapy for Samer Abou Ezzi, MS*; Makoto Urushitani, MD, PhD; Jean-Pierre Julien, glaucoma is to lower eye pressure by medication and/or surgery. However, a PhD. Department of Anatomy and Physiology, Laval University, Research significant proportion of patients continue to experience vision loss in spite Centre of CHUL, Quebec of responding well to pressure lowering drugs. Thus, it is clear that current therapeutic strategies for glaucoma are insufficient and new approaches to Recent studies suggest that superoxide dismutase (SOD1) may represent slow disease progression are urgently needed. Here we investigated the a major target of oxidative damage in neurodegenerative diseases. To test the neuroprotective effect of galantamine, a modest acetylcholinesterase possibility that oxidized species of wild-type (WT) SOD1 might be involved inhibitor and an allosteric potentiator of nicotinic receptors, in experimental in pathogenic processes, we analyzed the properties of the wild-type (WT) glaucoma. Galantamine has been approved by Health Canada and the U.S. human SOD1 protein after its oxidation in vivo or in vitro by H2O2 Food and Drug Administration for the treatment of Alzheimer’s disease: it treatment. Using transfected Neuro2a cells expressing WT or ALS-linked has few side effects, is taken orally by patients and has demonstrated efficacy SOD1 species, we show that exposure to H2O2 modifies the properties of in clinical trials for Alzheimer’s disease. The neuroprotective effect of WT SOD1. Western blot analysis of immunoprecipitates from cell lysates galantamine was tested in an experimental glaucoma model in which revealed that, like mutant SOD1, oxidized WT SOD1 can be conjugated with unilateral ocular hypertension was induced by injection of a hypertonic saline poly-ubiquitin and can interact with Hsp70. Chromogranin B, a solution (1.85 M NaCl) into an episcleral vein. Rats received daily neurosecretory protein that interacts with mutant SOD1 but not with WT intraperitoneal injections of galantamine (3.5 mg/kg) dissolved in sterile SOD1, was co-immunoprecipitated with oxidized WT SOD1 from lysates of saline solution. Treatment began on the first day of IOP increase and Neuro2a cells treated with H2O2. Treatment of microglial cells (line BV2) continued thereafter for the entire duration of the experiment. For RGC with either oxidized WT SOD1 or mutant SOD1 recombinant proteins density quantification, DiI-labeled neurons were counted in 12 standard induced tumour necrosis factor (TNF-α) and inducible nitric oxide retinal areas. RGC axons were counted in optic nerve semi-thin cross synthase (iNOS). Furthermore, exposure of cultured motor neurons to sections. Counts were performed in duplicate and in a masked fashion. Daily oxidized WT SOD1 caused dose-dependent cell death like mutant SOD1 systemic treatment with galantamine resulted in striking protection of RGCs proteins. These results suggest that WT SOD1 may acquire binding and toxic from ocular hypertension damage. In animals with pressure increase properties of mutant forms of SOD1 through oxidative damage. (ΔIOP) between 5-10 mmHg, galantamine preserved 90% of RGCs at 5 weeks after ocular hypertension surgery (n=10) compared with 65% of RGCs that survived in controls treated with saline (n=7). Galantamine was also more effective than donepezil (n=8), another acetylcholinesterase DISORDERS OF THE NERVOUS SYSTEM inhibitor, or memantine (n=8), an NMDA receptor blocker. Our results also demonstrate that daily administration of galantamine did not reduce IOP. To further confirm that galantamine-induced neuroprotection was independent 115 A103 of changes in eye pressure, we examined its effect following optic nerve ANIMAL STUDIES OF COMORBIDITY BETWEEN MOOD axotomy. In this model, intraocular injections of galantamine dramatically DISORDERS AND COCAINE DEPENDENCE; BEHAVIOURAL increased the survival of RGCs. Collectively, these results demonstrate three CHARACTERISTICS OF AN ‘AT RISK’ PHENOTYPE important properties of galantamine: i) it promotes robust protection of Craig Allen*, Martin Sticht, Anne Marie Levy, Shabdis Djazayeri, Mark RGCs in different models of optic nerve damage, ii) it is effective when Tucci and Francesco Leri. Department of Psychology, University of Guelph administered systemically or by intravitreal injection, and iii) its neuroprotective effect is not caused by reduction of IOP. Our data provide the The purpose of this study was to investigate the comorbidity between first demonstration of the clinical potential of galantamine as neuroprotective mood disorders and cocaine dependence using animal models of behavioral therapy for glaucoma and other optic neuropathies. despair and cocaine seeking. One hundred and twenty five rats were tested for individual differences in active struggling in an inescapable stressor (water). The same animals were then tested in operant chambers for 117 A105 responding to: 1) a novel audiovisual cue; 2) the same cue after its NEURONAL LOSS FOLLOWING CORTICAL TRAUMA: A association with infusions of cocaine (150 infusions in three sessions, 0.05 POSSIBLE ROLE IN EPILEPTOGENESIS mg/kg/inf); and 3) the same cue in tests of reinstatement induced by priming Sinziana Avramescu*, Dragos A. Nita, Igor Timofeev. Centre de Recherche injections of cocaine (15 mg/kg, IP) and exposure to foot-shock stress. It was Universite Laval Robert-Giffard, Quebec found that rats with the least amount of struggling showed the highest level of responding for the novel cue, as well as highest levels of cocaine seeking The incidence of chronic epilepsy following penetrating cortical wounds as measured by responding for after conditioning and during both tests of is more than 50%, however the mechanisms of post-traumatic epilepsy reinstatement. These findings suggest that propensity to behavioral despair remain largely unknown. Here we use the model of partially isolated is positively associated with novelty seeking and cocaine seeking. suprasylvian gyrus to test weather a change in the balance between the Supported by CIHR, CFI and OIT. number of excitatory and inhibitory neurons might explain the increased frequency of seizures observed after head trauma. All animals with chronic partially deafferented cortex developed paroxysmal EEG activities within 1

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month after cortical deafferentation. We labeled immunohistochemically all 119 A107 neurons with neuronal-specific nuclear protein antibody (NeuN) and only the WALLERIAN DEGENERATION INDUCED MICROGLIAL inhibitory neurons with gamma-aminobutyric acid antibody (GABA) or its REACTIVITY GENERATES A MIGRATORY SIGNAL(S) DRIVING synthesizing enzyme glutamic acid decarboxylase antibody (GAD 65 and THE MIGRATION OF OLFACTORY ENSHEATHING CELLS 67). The number of labeled neurons was quantified in sham animals and after (OECS) chronic (2, 4 and 6 weeks) cortical deafferentation, in suprasylvian and Basiri, M. and Doucette, R. Dept. Anatatomy & Cell Biology, University of marginal gyri, both ipsi- and contra-lateral to cortical trauma. In all animals Saskatchewan the neuronal loss was circumscribed to the deafferented suprasylvian gyrus. The total number of neurons in the undercut was reduced by 3.81% at 2 Olfactory ensheathing cells (OECs) are glial cells that are attractive weeks, 15.4% at 4 weeks and 17.4% at 6 weeks compared to sham animals. candidates for neural repair after spinal cord injury. We determined whether Nevertheless, there was no significant change in the number of neurons from OECs were induced to migrate in response to glial reactivity arising as a the contra-lateral suprasylvian gyrus, nor from the marginal gyrus ipsi- and result of Wallerian degeneration in the right dorsal corticospinal tract (dCST; contra-lateral to the traumatized cortex. The number of GABA-labeled left sensorimotor cortex injury) and compared their migratory path with inhibitory neurons was diminished by 18.5% at 2 weeks, 23.92% at 4 weeks respect to the location of reactive microglia (i.e. inside vs outside the right and 56.34% at 6 weeks. Similarly, GAD-labeled neurons decreased with dCST). Groups 1 and 2 rats (n=4 for each) each received left sensorimotor 26.25% at 2 weeks, 35.87% at 4 weeks and 57.05% at 6 weeks after cortex lesions, whereas Groups 3 and 4 rats (n=4 for each) served as deafferentation. Furthermore, the ratio between excitatory and inhibitory unlesioned controls. DiI-labelled OECs were injected into the right dorsal neurons increased from 5.01 at 2 weeks following trauma to 10.02 at 4 weeks funiculus of T12 in all 4 Groups, with the timing of this injection in Groups and 12.23 at 6 weeks respectively. The preferential loss of inhibitory neurons 1 and 2 being 8 weeks after the cortical lesion. Rats received daily i.p. might explain the high rate of chronic epilepsy observed in patients with head injections of either minocycline (Groups 1 and 3) or vehicle (Groups 2 and trauma. Moreover, the global neuronal loss (both excitatory and inhibitory 4) beginning 2 weeks prior to and ending 4 weeks after the OEC grafts. All neurons) may account for the frequent cognitive impairments of children rats were killed 8 weeks after cell grafting and cell counts of DiI+ve OECs who develop epilepsy early in life. Supported by CIHR and NSERC were computed separately for the right and left dCSTs and dorsal funiculus of T11. The glial reactivity was confined to the right dCST and was present only in Groups 1 and 2; in Group 1 rats minocycline diminished the Wallerian-degeneration induced microglial response. In comparison to 118 A106 vehicle treated unlesioned control rats (i.e. Group 4), there was a ASSESSING THE SUBJECTIVE VISUAL VERTICAL AND THE significantly higher density of DiI+ve OECs only for the right dCST of PERCEPTUAL UPRIGHT IN PARKINSON’S DISEASE Group 2 (i.e. cortical lesion and vehicle treated) rats; thus, the migratory path *Barnett-Cowan, M., Sanderson, J., Dyde, R. T. & Harris, L. R. (1). (1) was only where microglia were reactive. The density of DiI+ve OECs in the Multisensory Integration Laboratory, Centre for Vision Research, Dept. right dCST was significantly lower in Group 1 rats (i.e. minocycline treated) Psychology, York University compared to Group 2 rats (i.e. vehicle treated); thus, dampening the microglial response also reduced the migratory signal(s). Funded by a grant Previous reports have suggested that patients with Parkinson’s disease from the MS Society of Canada to RD and by a scholarship from Ministry of have increased visual dominance for spatial perception tasks. We therefore Health and Medical Education, Iran to MB assessed the relative roles of visual and non-visual cues in determining the subjective visual vertical (SVV) and the perceptual upright (PU) in patients with Parkinson’s disease using a luminous line and the newly developed 120 A108 OCHART test (Dyde et al., 2006; Exp. Brain. Res. 173; 612). We tested the TEA CATECHINS PROTECT HIPPOCAMPAL NEURONS hypothesis that patients with Parkinson’s disease rely more on visual cues AGAINST BETA-AMYLOID-INDUCED TOXICITY than non-visual cues for spatial perception. Visual cues for both the SVV and S. Bastianetto & R. Quirion. Douglas Research Centre, Department of PU were manipulated using a grey background, a static frame tilted +/- 18º, Psychiatry, McGill University, 6875 Blvd Lasalle, Verdun, Québec and a static visually enriched polarized room tilted 18º, 112.5º, 247.5º, and 342º clockwise (all orientations are relative to the observer). To measure the Accumulating evidence suggests that consumption of polyphenols relative contributions of visual, vestibular and body orientation cues, patients derived from beverages, fruits and vegetables have a beneficial impact in were tested while seated upright and while lying on their right side. reducing the incidence of dementia. Considering the deleterious role of beta- Parkinson’s patients were tested while on and off of their prescribed amyloid (Aß) in the etiology of Alzheimer’s disease (AD), we investigated dopaminergic medications and compared to an age-matched control group. green and black tea extracts and their ingredients against toxicity induced by No differences were found attributable to medication. Patients with Aß-derived peptides using primary rat hippocampal cell cultures. Both green Parkinson’s disease were found to have significantly higher variance for both and black tea extracts when you say extracts, how can you write (5-25 µg/ml) the SVV and PU tasks compared to the aged-matched control group. We displayed neuroprotective action against Aß toxicity. These effects were confirmed that when upright, patients with Parkinson’s disease are more shared by gallic acid and catechin gallate esters known as epicatechin gallate influenced by visual cues than aged-matched controls for the SVV task. (ECG; 1-20 µM) and epigallocatechin gallate (EGCG; 1-10 µM), the former However, when tested lying on their sides, the control group was found to be being the most potent catechin. In contrast, epicatechin and epigallocatechin more influenced by visual cues for the SVV task. When both body were ineffective in the same range of concentrations. Moreover, EGCG, and orientations were taken together patients with Parkinson’s disease were to a lesser extent ECG and gallic acid, inhibited Aß fibrils/oligomers found to be more influenced by body orientation than visual cues for the formation at the same concentration, they protected cells. Taken together, SVV task. The PU in patients with Parkinson’s disease was found to be less these results indicate that the catechin gallates (through the galloyl moiety) influenced by visual cues than controls. We conclude that across different contribute to the neuroprotective effects of both green and black teas. body postures, patients with Parkinson’s disease are more influenced by the Moreover, these results suggest that protective effect of EGCG is likely due, orientation of their body than visual cues in spatial perception tasks. at least in part, to its inhibitory action on Aß fibrils/oligomers formation. These data also support the hypothesis that both green and black teas may prevent neurological disorders in which Aß formation likely plays a deleterious role. Supported by CIHR.

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121 A109 preliminary analysis indicates AMPH-induced DA release compared to LOSS OF HETEROZYGOSITY ON 22 CHROMOSOME IN baseline in the dorsal (caudate and putamen) and ventral striatum, with a SPORADIC SCHWANNOMAAND ITS CORRELATION TO THE significant effect in the latter (p<0.03). AMPH-induced DA release was also PROLIFERATION OF TUMOR CELL observed in the depressed PD subjects. Placebo-induced DA release was LG. Bian (1), (2), W. Tirakotai (2), WG. Zhao (1), JK. Shen (1), QZ. Luo (3). observed in all PD subjects, in particular the putamen of the depressed (1) Department of Neurosurgery, Rui-Jin Hospital, Shanghai Second Medical subject. As well, preliminary results suggest enhanced AMPH-induced DA University, Shanghai, The People’s Republic of China (2) Department of release in the dorsal striatum of the depressed patient compared to non- Neurosurgery, Philipps University, Marburg, Germany (3) Department of depressed PD patients. Ongoing work will attempt to extend these findings Neurosurgery, Ren-Ji Hospital, Shanghai Second Medical University, to a larger sample. Shanghai, The People’s Republic of China

Most of studies of neurofibromatosis type 2 (NF2) gene were studied in 123 A111 the vestibular schwannomas. It is unknown whether there are different EFFECTS OF DIETARY OMEGA-3 POLYUNSATURATED FATTY genetic alterations between vestibular schwannoma and non-vestibular ACID ON TOXIN-INDUCED NEURONAL DEGENERATION IN schwannoma or not. Therefore, We analyze the loss of heterozygosity (LOH) PARKINSON’S DISEASE ANIMAL MODELS on chromosome 22 (CHR 22) in patients harboring sporadic schwannomas Mélanie Bousquet1,2*, Martine Saint-Pierre1, Carl Julien2, Francesca (including vestibular and spinal schwannomas ) and correlate this genetic Cicchetti1,3, Frédéric Calon2. 1 Centre de Recherche en Neurosciences, alteration with the tumor’s proliferation. Twenty three schwannomas (42.6%) Université Laval, CHUL, Québec 2 Centre de Recherche en Endocrinologie showed allele loss. The frequency of LOH in vestibualr schwannomas was Moléculaire et Oncologique et Faculté de pharmacie de l'Université Laval, significantly higher than corresponding value in spinal schwannomas Québec,Département de Médecine, Université Laval, Québec (p<0.01). The proliferative index of schwannoma with LOH was significantly higher than those without LOH (p<0.05). Our findings suggest Parkinson’s disease is a neurodegenerative disorder characterized by the that CHR 22 LOH is the frequent event in the tumorigenesis of sporadic massive death of dopaminergic nigrostriatal neurons. The resulting schwannoma. And there is the correlation between tumor harboring CHR22 diminution of striatal dopamine affects voluntary movements and causes LOH and its proliferative activity. The frequency of LOH in vestibular symtoms such as resting tremor, akinesia, rigidity and postural instability. schwannoma is different from it in the spinal shcwannomas. Accumulating evidences suggest that the fatty acid we eat may have a direct impact on brain health. Neuroprotective action of long chain omega-3 polyunsaturated fatty acid (n3PUFA) such as docosahexaenoic acid has been 122 A110 demonstrated in animal models of Alzheimer’s disease and is supported by AMPHETAMINE-INDUCED DOPAMINE RELEASE IN epidemiological data. We hypothesized that n3PUFA may exert neuro- PARKINSON’S DISEASE DEPRESSION MEASURED USING protective action in Parkinson’s desease as well. To test this hypothesis, we HIGH-RESOLUTION POSITRON EMISSION TOMOGRAPHY exposed mice to either low or high intake of n3PUFA before acute MPTP WITH [11C] RACLOPRIDE treatment, which included seven injections of MPTP (20 mg/kg) in five days. E Bogusz*, SC Lidstone, K Dinelle, S Blinder, TJ Ruth, LN Yatham, V Sossi, The duration of pre-treatment exposure to differential n3PUFA diets was of AJ Stoessl. The Pacific Parkinson's Research Centre, Vancouver Hospital 8 months. Post-mortem analyses in the brain of mice exposed to MPTP did adn Health Sciences Centre, University of British Columbia, Vancouver not show a significant effect of dietary n3PUFA on tyrosine hydroxylase Brain Research Centre, University of British Columbia, Vancouver TRIUMF, (TH) striatal fibers, TH positive nigral cells and levels of Nurr1 mRNA, as University of British Columbia, Vancouver assessed by in situ hybridization. However, HPLC (electrochemical detection) analyses showed that mice fed with a high n3PUFA diet were Depression affects around 40% of patients with Parkinson’s disease (PD), partially protected from MPTP-induced decrease in striatal dopamine and which is nearly double the amount of severe depression seen in comparably dihydroxyphenylacetic acid (DOPAC) compared with mice fed with low disabled patients with other chronic illness. Mesocorticolimbic dopamine n3PUFA diet. These data suggest that higher n3PUFA dietary intake might (DA) depletion has been implicated in the pathogenesis of depression (Remy exert a neuroprotective action in an animal model of parkinsonism. Since the et al. 2005), and thus may contribute to the high incidence of depression in prevalent low consumption of n3PUFA might be an important modifiable PD. Amphetamine (AMPH)-induced striatal DA release was compared risk factor of Parkinson’s disease, our data call for further investigation on between depressed (n=1) and non-depressed (n=4) patients with PD using the neuroprotective effect of n3PUFA in neurodegenerative diseases. positron emission tomography (PET). DA release was estimated by displacement of the D2/D3 receptor radiotracer [11C]raclopride (RAC). Subjects completed three scans over two days within a three month period. 124 A112 The first scan was a baseline scan, followed by either blinded d-AMPH (0.3 NEUROANATOMICAL DEFICITS FOLLOWING MODERATE mg/kg p.o.) or placebo administration, counterbalanced across subjects. PRENATAL ETHANOL EXPOSURE IN THE NON-HUMAN Severity of depression was assessed using the Montgomry Asperg PRIMATE Depression Rating Scale. The subjective response to AMPH or placebo was Mark W Burke 1*, Roberta Palmour 2,3, Denis Boire 4, Raphael Vezina- measured using an Amphetamine Interview Rating Scale after the PET scans. Audette 5, Sabrina Bourget-Coulombe 5, Maurice Ptito 5, Frank Ervin 2,3. Following the bolus injection of ~350 MBq of RAC for each scan, emission 1 Department of Physiology, 5 École d'optométrie, Université de Montréal. 2 data were acquired for 60 minutes on an ultra high resolution research Department of Psychiatry, McGill University. 3 Behavioral Science tomograph (HRRT, Siemens) and scans were reconstructed using Ordinary Foundation, St. Kitts. 4 Départment de chimie-biologie, Université du Poisson-OSEM including attenuation, scatter and random correction. To Québec à Trois-Rivières correct for motion during the scans inter-frame realignment was performed using automated image registration. Circular and elliptical regions of interest Fetal alcohol syndrome (FAS) is a consequence of heavy maternal of interest were placed on 9 transaxial slices for the dorsal striatum (total drinking during pregnancy and results in craniofacial dysmorphology along thickness 10.89 mm), 6 coronal slices for the ventral striatum (total thickness with an array of neurobehavioral deficits. The much more prevalent spectrum 7.26 mm) and 6 transaxial slices for the cerebellum. RAC binding potentials disorder (FASD), a consequence of moderate maternal ethanol consumption, (BP) were estimated using a graphical tissue approach (Logan et al. 1996) also causes neurobehavioral deficits. However, despite its clinical with the cerebellum as a reference region. In non-depressed PD subjects, prevalence, little is known about moderate exposure on the cortical neuronal

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population. A small number of imaging studies of FAS/D patients suggest a and males. The time course of PE evoked by capsaicin also differed between reduced cranial vault volume, however these techniques lack the ability to males and females. The time to reach maximum PE was significantly longer detect cellular loss. Using a naturalistic non-human primate model of FASD, in estrus females (35 minutes) compared to non-estrus females (29 minutes) vervet monkeys (Chlorocebus aethiops sabeus) were exposed to moderate and males (7 minutes). This study has revealed that PE in the facial skin is levels of ethanol during the period of rapid synaptogenesis. During the third significantly greater in females in the estrus stage of their cycle compared to trimester of gestation, socially-housed female vervet monkeys voluntarily non-estrus females and males. We propose that differences in the drank an average of 2.22 ± 0.36 g/kg ethanol/day resulting in an average inflammatory response evoked by capsaicin may be due to changes in the blood alcohol content of 0.01 ± 0.0016 g/dL (21.7 ± 3.5 mM), or isocaloric level of neuropeptide expression and primary afferent sensitivity caused by sucrose (control) four times a week. None of the offspring showed the surge in estrogen that occurs prior to estrus. These findings may help to craniofacial dysmorphology and were neuroanatomically examined at 2 explain why females are over represented in several pathological conditions years of age. The left hemisphere along with the cerebellum were serially associated with the trigeminal territory, such as migraine, trigeminal sectioned and stained with cresyl violet. Stereology was used to determine neuralgia and temporomandibular joint disorder. vulnerable brain regions. The cerebellum, cerebral cortex and hippocampus were identified as particularly vulnerable brain regions with the cerebral cortex and hippocampus showing the greatest neuronal loss. Subjects 127 A115 exposed to prenatal ethanol had a 30% neuronal deficit in the cerebral cortex DETERMINATION OF THE ROLE OF SAP97 IN MOTOR and a 67% neuronal loss in the hippocampus. This is the first study to provide ABNORMALITIES IN 6-HYDROXYDOPAMINE-LESIONED RAT a detailed neuroanatomical analysis of the non-human primate following MODEL OF PARKINSON’S DISEASE prenatal ethanol exposure and not only corroborates volume loss seen in Vitali Chatalov*, Ruth Warre, and Joanne E. Nash. Life Sciences Department FASD patients but suggest that this loss is caused by extensive neuronal loss. at the University of Toronto at Scarborough The model described here provides a tool for prompt and quantitative evaluation of intervention strategies and will facilitate safe and timely In Parkinson’s disease (PD), loss of striatal dopamine causes dysfunction translation to the clinical setting. of multiple neurotransmitter receptor signaling pathways, in particular glutamate. This is reflected by alterations in expression levels of receptors at the synaptic membrane, such as dopamine and glutamate, which plays a role 125 A113 in the generation of symptoms of PD. Within the postsynaptic density (PSD), HIGH-DOSE METHADONE MAINTENANCE ATTENUATES synaptic proteins play a crucial role in trafficking, anchoring and down- COCAINE-INDUCED BEHAVIORAL SENSITIZATION IN THE stream signaling of receptors. Synapse associated protein 97 (SAP97), a RAT member of MAGUK family of scaffolding proteins, is particularly well Brendan Carmichael, Erin Cummins and Francesco Leri. University of known for its role in receptor trafficking, and appropriate targeting of Guelph receptors to the synaptic membrane. Interestingly, studies have shown that, in unilaterally-lesioned 6-OHDA rats, SAP97 is dramatically decreased at The purpose of this study was to investigate whether high-dose striatal synapses and redistributed into the vesicular fraction (Nash et al., methadone maintenance (HDMM) could reverse an effect of chronic cocaine 2005). A similar study showed that striatal SAP97 was reduced in a PSD- exposure associated with its compulsive use, namely: behavioral enriched fraction in 6-OHDA-lesioned rats (Gardoni et al., 2006). Therefore, sensitization. To this end, rats received one test of basal sensitivity to we hypothesized that changes in the levels of SAP97 in striatum are part of cocaine-induced stimulation of locomotion (15 mg/kg, IP). They then the molecular mechanism leading to the motor symptoms of PD. Thus, the received 3 injections per day of cocaine (15 mg/kg each, IP) for 14 days. effects of striatal over-expression of SAP97 on motor abnormalities Following this period, they were implanted (SC) with osmotic mini-pumps displayed by 6-OHDA-lesioned parkinsonian rats were tested. The N- releasing 30 mg/kg/day methadone for 14 days. Ten days following removal terminus of SAP97 appears to be necessary for trafficking and targeting of of the pumps, the animals received a second test of cocaine-stimulated glutamate receptors to the synaptic membrane. Given the importance of N- locomotion (15 mg/kg, IP). It was found that cocaine exposure induced terminal domain of SAP97 for trafficking, its involvement in parkinsonism robust behavioral sensitization as indexed by the emergence of intense was assessed. SAP97 mutants with N-terminal deletions of amino acids 1-65 stereotypy. More importantly, this effect was significantly reduced by or 66-125 were used. Adenovirus vectors encoding either, GFP (control); HDMM which, by itself, induced no cross-sensitization. SAP97-GFP (wild type); SAP97Δ1-65-GFP (minus 1-65 a.a. of the N- terminal domain) or SAP97Δ66-125-GFP (minus 66-125 a.a.) were injected into the striatum of the operated side of unilaterally-lesioned 6- 126 A114 OHDA rats and sham-operated animals. Twenty one days post 6-OHDA SEX DIFFERENCES IN CAPSAICIN-INDUCED PLASMA lesion, forelimb asymmetry was measured. This was then repeated following EXTRAVASATION IN RAT FACIAL SKIN intraperitoneal injection of L-DOPA methyl-ester. 6-OHDA lesions caused a Carmichael NM.*, Charlton MP, Dostrovsky JO. University of Toronto. Dept. 4-fold increase in limb-use assymmetry (ANOVA, F(7,86) = 8.63, P<0.001). of Physiology, University of Toronto Over-expression of wild type SAP97 and mutant constructs alone did not restore limb-use asymmetry in 6-OHDA lesioned rats. However, following Capsaicin stimulates pain receptors and causes an inflammatory response L-DOPA methyl-ester administration, limb-use asymmetry was corrected in characterized by vasodilation and plasma extravasation (PE). Since there are 6-OHDA-lesioned rats over-expressing wt SAP97-GFP and SAP97Δ1- many reports of sex differences in pain, we asked whether there are sex 65-GFP but not SAP97Δ66-125-GFP. Thus, SAP97 over-expression differences in the inflammatory response evoked by capsaicin. We compared potentiated the anti-parkinsonian effect of L-DOPA. Furthermore, 66-125 the amount of PE in the facial (V1, caudal to eye) region of male and female a.a. region of N-terminal of SAP97 was found to be important for this rats caused by subcutaneous injection of capsaicin (1%, 20uL). PE was function. These results suggest that changes in levels of SAP97 in the quantified using a video camera and digital image analysis to measure parkinsonian striatum may affect dopamine receptor signaling. Biochemical changes in reflectance (pixel intensity, PI) of rat skin due to accumulation of studies are currently underway to measure the sub-cellular distribution of extravasated Evans Blue (EB) dye. Capsaicin-induced PE was significantly SAP97 and dopamine receptors, which may be responsible for the observed greater in female rats in estrus (85.7 +/- 5,PI) compared to males (60.2 +/- behavioral changes. 4.5, PI) and non-estrus females (52.1 +/- 4.8, PI) (ANOVA, Post-hoc Tukey, P < 0.001, n = 6). There was no difference in PE between non-estrus females

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128 A116 130 A118 LIVE IMAGING OF ASTROGLIOSIS IN CEREBRAL ISCHEMIA CHANGES IN LOCAL FILED POTENTIALS IN THE REVEALS NEURONAL DAMAGE IN MALE BUT NOT IN CEREBELLAR THALAMUS AND SUBTHALAMIC NUCLEUS FEMALE EVOKED BY STIMULATION OF THE CONTRALATERAL *Pierre Cordeau Jr.§, Mélanie Lalancette-Hébert§, Yuan Cheng Weng and NUCLEI Jasna Kriz* Department of Anatomy and Physiology, Laval University G. Descalzi*(1), P. Pakarian(1), E. Moro(2), M. Hodaie(3), A. Lozano(3), R. (CHUL) Chen(1). 1) Neurology, Toronto Western Research Insti, Toronto. 2) Neurology, Toronto Western hospital, Toronto 3) Neurosurgery, Toronto Reactive astrogliosis is one of the key components of the cellular Western Research Insti, Toronto responses to brain injuries and the passage from the quiescent to reactive astrocytes is associated with strong up-regulation of the intermediate We recorded the evoked potentials of thalamus and sub-thalamic nucleus filament, glial fibrillary acidic protein (GFAP). (STN) regions by stimulating their contralateral counterpart. Two patients The main objective of this study was to develop model-system for live participated in this study. One patient had bilateral deep brain stimulation analysis of brain inflammatory response in ischemic injury. Methods: Using (DBS) electrodes implanted in the ventro-intermediate nucleus (Vim) of the a reporter mouse expressing luciferase gene under the transcriptional control thalamus for treatment of essential tremor. The other patient had bilateral of murine GFAP promoter (GFAP-luc mice, Xenogen) and biophotonic/ DBS electrodes implanted in the sub-thalamic nucleus for treatment of bioluminescent imaging as tools we developed a model-system for in vivo Parkinson's disease. Both patients were studied 2 to 5 days after the analysis of astrocyte activation/response in cerebral ischemia. Unilateral implantation of the DBS electrodes, when the leads were still externally transient focal cerebral ischemia was induced by intraluminal filament exposed. Local field potentials were recorded from all four contacts of the occlusion of the left MCA during 1 hour followed by imaging session with a DBS electrodes while stimulation was applied to the contralateral DBS high resolution/high sensitivity CCD camera at 24 hours, 72 hours, 5 and 7 electrode at different frequencies, intensities and contact combinations. days after surgery. Results: The analysis of photon emissions from the brains Results: Right Vim stimulation elicited potentials in the left Vim electrodes of living animals revealed that the intensities of GFAP signals after stroke with peak latencies of ~12 ms (contact 2+), ~30 ms (contact 2- ) and 70 ms were significantly higher in female compared to male transgenic mice (contact 0-). Latencies and polarities were similar with stimulation of (1.652x107±0.19 p/s vs 0.747x107±0.14 p/s, p<0.001). This effect was different contacts in the left Vim. The evoked potentials in the frequency abolished by ovariectomy. Similar results were obtained by quantitative domain can be described as the activity of two cosine oscillators, one of them immunohistochemistry (males,13.4±0.5 vs 16.96±0.64 p<0.0001,females). A starts at phase zero and oscillates 3.5 cycles and the other starts at phase Pi three-dimensional analysis confirmed that GFAP signals followed the pattern and oscillates at 2.5 cycles until 150 milliseconds post stimulus. Stimulation of GFAP immunoreactivity and were emitted from the brain areas of the left STN elicited a positive potential in the right STN at contact 0 with surrounding the ischemic lesions. Further, contrary to the positive correlation a latency of about 65 ms. These STN potentials were most prominent with between the intensities of GFAP signals and the size of the infarction in male stimulation of the lowest contact (0) and diminished with stimulation of mice, there was no correlation between signal intensities/GFAP induction higher contacts. and the size of ischemic lesion in female GFAP-luc mice. Interpretation: The real-time imaging data revealed remarkable gender difference in the astrocyte response to ischemic injury. Our results suggest that GFAP up- 131 A119 regulation induced by ischemic injury may have different functional AMYGDALA RESPONSE TO BACKWARD MASKED EMOTION IN significance in female and male experimental animals and may not directly AUTISM reflect the extent of ischemia-induced neuronal damage in female GFAP-luc 1West, C. Dianne, 1,2 Goldberg, Jeremy, *1Doyle, Krissy A.R., 1,2 Szatmari, mice. Using novel live imaging approach we demonstrated that early-phase Peter, 1,2 Hall, Geoffrey B.C. 1 Department of Psychiatry and Behavioural brain inflammatory response to ischemia may be associated with gender- Neurosciences, McMaster University, Hamilton, Ontario, Canada. L8N 3Z5. related brain injury markers. 2 Offord Centre for Child Studies, Hamilton

Subconscious presentation of negative face stimuli to typically developed 129 A117 adults increases neural activity in the amygdala (Morris et al., 1998). METHYLATION ANALYSIS OF THE 5-HT2A RECEPTOR GENE However, Hall et al. (in press) have found that the social decisions of children 102C ALLELE BASED ON DIFFERENTIAL EXPRESSION AND with autism are less influenced by subconscious presentation of negative face PARENT-OF-ORIGIN EFFECT IN SUICIDAL BEHAVIOR stimuli, than controls. As such, it is suggested that information normally Vincenzo De Luca, James L. Kennedy, Albert H.C. Wong. Centre for available at the amygdala through subcortical routes is reduced in autism. Addiction and Mental Health, Department of Psychiatry, University of The purpose of this study was to examine amygdala activation induced by Toronto subconscious presentation of negative face stimuli in high functioning adult males with autism. Ten high functioning males with autism and matched The serotonin 2A (5-HT2A) receptor gene has been implicated in the male controls participated. All participants gave informed consent, were pathogenesis of suicidal behaviour by a genetic association between the 5- right handed and had no known neurological or psychiatric disorders, drug or HT2A T102C silent polymorphism and suicidality in patients with major alcohol abuse or history of head trauma. Stimuli were presented to the depression. However, a recent meta-analysis failed to confirm this participants in the MRI scanner via an overhead visor, with responses made association. We developed an improved quantitative assay for the via a hand-held response pad. Functional BOLD imaging was done using an measurement of allele-specific expression of the 5-HT2A gene, and find that interleaved echo-planar imaging sequence with TR=2700ms, TE=35ms. the ratio of C/T allele expression in the pre-frontal cortex of heterozygous Sixty-four neutral (32 male and 32 female) and 64 fearful face stimuli were suicide victims (n=10) was significantly decreased in comparison with the used in an event related design. Participants were presented a neutral face non-suicide group (n=10) (p=0.049). Because the 5-HT2A gene is subject to (mask) and asked to identify whether the face was male or female. The imprinting, the parent-of-origin may affect the inheritance of suicidal presentation of neutral face was interupted at fixed intervals by two behaviour. Thus we examined the parental origin of specific alleles for subthreshold (33 msec) presentations of a fearful face. Each trial was 2700 genetic association in a genetic family-based sample of major psychoses in ms in duration, and was followed by a fixation stimulus. The intertrial which information on suicidal behaviour was available. This result suggests presentation was jittered, with delays between 2700 ms and 8100 ms the methylation quantification of the 102C allele in suicide and non-suicide (average 5400 ms). Data analysis is underway, however, preliminary results groups.

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identify that in controls backward masking produced amygdala activation. In platform. Naïve animals and animals that received up to 6 low doses of contrast, at the same threshold level, activation of visual association areas pilocarpine without developing SE (post-pilo) learned the task (6 sec latency) and no activation of the amygdala is seen in the data of a subject with autism. within 6 days. In contrast, reference learning was grossly impaired in SE rats, with only modest improvement occurring over repeated days (32 sec latency). Reversal learning involved relocating the platform to the opposite 132 A120 quadrant of the pool. Naïve and post-pilo animal groups learned the task THE ROLE OF BRAIN INFLAMMATION IN A NEONATAL within a single day, whereas SE animals failed to show any acquisition within VENTRAL HIPPOCAMPUS-LESIONED ANIMAL MODEL OF 5 days. The elevated plus maze is a validated test for investigating anxiety SCHIZOPHRENIA and exploratory behaviour. The naïve and post-pilo animal groups spent 1Drouin-Ouellet J., 1Saint-Pierre M., 2Lévesque D., 1,3Cicchetti F. 1Centre approximately 86% of the time shielded in the closed arm, and exhibited de Recherche en Neurosciences, CHUL, RC-9800, 2705, Boulevard Laurier, frequent exploratory behaviour (rearing, lookouts). In contrast, the SE animal Québec; 2 Département de Pharmacie, Université de Montréal, C.P. 6128 group spent approximately 50% of the time in the closed arm, and showed Succ. Centre-ville, Montréal; 3Département de Médecine, Université Laval, virtually no exploratory behaviour. The present data demonstrates that the Québec RLD procedure for inducing status epilepticus results in impaired cognitive function and altered anxiety and exploratory behaviour. Behavioural It has been hypothesized that a viral infection during the second semester performance is currently being correlated with the severity of neuro- of pregnancy may alter or trigger improper brain development of the fetus. degeneration in specific brain regions. Research supported by NSERC. Abnormal immune functions are also among the mechanisms postulated to play a role in the pathophysiology of schizophrenia, as indicated by increased serum concentrations of interleukin-6 (IL), IL-6 receptor, IL-IR antagonist 134 A122 and IL-2R in schizophrenic patients. Here we investigate the contribution of SURGICAL PATHOLOGIC FINDINGS IN THE INTRACTABLE the inflammatory response to this pathology using a rat model generated by TEMPORAL LOBE EPILEPSY ibotenic acid lesions. This model, for which the lesion is performed at post- Estupiñán Díaz B.*, Morales Chacón L.M., Lorigados Pedre L., García natal day (p)7, produces an irreversible disconnection of the ventral Maeso I.,. Hidalgo Portal L., Orozco Suárez S. 1. International Center for hippocampus, which replicates a schizophrenic-like phenotype in adulthood, Neurological Restoration, Havana City, Cuba. 1 National Medical Center, as assessed by amphetamine-induced behavioral analyses. The pathological Hospital Siglo XXI, Instituto Seguro Social, México and behavioral analyses are more specifically performed at two time points, p35 (corresponding to pre-puberty) and p56 (corresponding to adulthood). Background and Purpose: Hippocampal sclerosis is often associated with Preliminary results reveal a pronounced microglial activation at p17 (10 days dysplasia in the temporal neocortex from patients with intractable epilepsy. post-lesion), as detected by the presence of several microglial cells (Iba-1 The aim of this study was identify neuropathological features in neocortex staining) and macrophages (ED-1 marker) at the site of lesion. Evidence of from temporal lobe epileptic patients. Materials and Methods: The study an inflammatory response are thus present several days before the included resected specimens from 17 patients with intractable temporal lobe development (p56) of behaviors corresponding to schizophrenia. Although epilepsy. All tissues were fixed in 10% buffered formalin, embedded in these results are very preliminary, they suggest that an inflammatory paraffin, cut at 6 m thick and stained with hematoxilyn – eosin and response may be preceding and contributing to schizophrenic signs which Klüver-Barrera. In selected cases immunohistochemical reaction (GFAP and appear during or post-adolescence. Current analyses include a time course of synaptophysin) was performed. Results: The studied group consisted of 10 inflammatory events within the first 24 h after the ibotenic acid lesions. females and 7 males, mean age of 37.7 years (range, 22 to 52 years). All Inflammatory molecules such as Il-1, TNF-, IL-6 and Cox-2 are being patients had mesial temporal sclerosis on magnetic resonance imaging. Dual analyzed in this model. Further studies include the anti-inflammatory pathology was identified in 12 patients (70.5%). In 11 patients (64.7%) focal treatment of these animals in an attempt to prevent the development of the cortical dysplasia was identified according to Palmini classification. The schizophrenic phenotype. most common patterns of dysplasia included: isolated architectural abnormalities (type IA) in 6 cases, giant neurons (type IB) in 4 cases and dysmorphic neurons (type IIA) in one case. White matter neuronal 133 A121 heterotopia was observed in 11 patients (64.7%). Diffuse accumulation of THE REPEATED LOW-DOSE PILOCARPINE MODEL OF STATUS corpora amylacea were demonstrated in 3 patients. One case of aracnoid cyst EPILEPTICUS ALTERS COGNITIVE AND BEHAVIOURAL was observed. The neuropathological features were regarded as non-specific FUNCTIONING IN ADULT RATS in 29.4% of cases. Conclusions: The medial temporal lobe epilepsy is Dykstra CM*, Joseph J, Joy J, Gurd J.W. Centre for the Neurobiology of associated with neuropathological changes in the neocortex. Dual pathology Stress, Department of Life Sciences, University of Toronto Scarborough, was a common finding in our patients with temporal lobe resection. Toronto

Status epilepticus (SE) is defined as continuous seizure activity that lasts 135 A123 for at least 30 minutes. The pilocarpine model of epilepsy is widely used REDUCED PREFRONTAL CORTEX DARPP-32MRNA IN experimentally to investigate SE and secondary generalized seizures that COMPLETED SUICIDE VICTIMS WITH SCHIZOPHRENIA evolve following a latent period (Turski et al., 1989. Synapse, 3, 154-171). Feldcamp, L.A*., de Souza, R., Romano-Silva, M., Kennedy J.L., Wong, Repeated low-dose administration of pilocarpine (10 mg/kg) in lithium A.H.C. Centre for Addiction and Mental Health, Departments of Psychiatry chloride pretreated Wistar rats results in low mortality rates, while producing & Pharmacology, University of Toronto SE and chronic epilepsy in a high proportion of the rats (Glein et al., 2001. Epilepsy Res, 46, 111-119). We investigated the extent of cognitive and Dopamine-and-cAMP-regulated neuronal phosphoprotein (32 kDaltons) behavioural deficits, assessed through performance in the Morris water maze (DARPP-32), encoded by PPP1R1B, is expressed in brain regions receiving (MWM) and elevated plus maze, in chronically epileptic rats at 2 months dopaminergic projections, including the prefrontal cortex, and is implicated following SE induction using the repeated low-dose (RLD) procedure. in the pathophysiology of schizophrenia and other neuropsychiatric Approximately 60% of Wistar rats developed SE using the RLD procedure, disorders. As a key regulator of kinase-phosphatase signaling cascades with a low mortality rate of 18%. During MWM training, Wistar rats related to dopaminergic, glutamatergic and serotonergic neurotransmission, received 6 trials per day, for a total of 14 days to locate a submerged DARPP-32 also plays a role in regulating the state of phosphorylation and

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activity of phosphoproteins such as voltage-dependent Ca+ and Na+ TgCRND8 mice express a transgene encoding a double mutant channels, Na+/K+-ATPase, and other neurotransmitter receptors in the brain. (KM670/671NL plus V717F) form of human APP. These animals exhibit The broad functional capacity of DARPP-32 has potential relevance to both spatial reference memory deficits that are readily discerned in Morris water psychotic and negative symptoms of schizophrenia. We performed RT-PCR maze tasks. It has been reported that the emergence of spatial memory to quantify DARPP-32 mRNA using fluorescent sequence-specific primers deficits coincides with the appearance of plaques at 15 weeks (Hyde et al., on brain samples donated by the Stanley Medical Research Institute (array 2005, Behav Brain Res 160:344-355), although we have seen spatial memory collection). These RNA samples, from Brodmann Area 46 in the prefrontal impairment as early as 11-12 weeks (Janus et al., 2000, Nature 277:602-8). cortex, included 35 brains each from unaffected controls (NC), patients with Cortical short-term memory deficits, such as object recognition impairment, schizophrenia (SCZ), or bipolar disorder (BP). Relative mRNA expression occur early in development of the human disease. To determine whether was calculated from a standard curve and in relation to the housekeeping cortical memory deficits precede plaque accumulation in the TgCRND8 gene glyceraldehyde-3-phosphate dehydrogenase (GAPDH). We found a mouse, we assessed acute Novel Object Recognition (NOR) memory. We significant difference in gene expression levels between SCZ patients that found that TgCRND8 mice exhibit profound NOR deficits at 8 but not at 4 died by suicide (S-SCZ) vs. other causes of death (SCZ-NS) (p<0.004), as weeks. Eight week old TgCRND8 mice were not impaired on a Morris water well as between S-SCZ and NC (P<0.04). DARPP-32 mRNA expression maze task. Optokinetic responses and duration of object exploration did not differences between S-SCZ and SCZ-NS suggests a potential molecular differ between TgCRND8 and non-Tg control mice. The presence of NOR explanation for suicidal behaviour in this population. Replication and further deficits in young mice suggests that rhinal cortices are affected early in the work is required to understand these preliminary results. disease process. Given that protofibrillary forms of amyloid have been shown to interact with mitochondria (Devi et al., 2006, J. Neuroscience 26:9057-68), we assessed complex I + III and IV activities in the 136 A124 hippocampus and cortex. In aged TgCRND8 mice with extensive plaque PROTEOMIC ANALYSIS OF NITROTYROSINE FORMATION pathology, we observed ~45% reduction in complex I + III activity. In FOLLOWING STROKE REVEALS A NEUROPROTECTIVE contrast, 9 week old TgCRND8 mice exhibited increased activity of complex RESPONSE AT THE SYNAPSE F140 I + III in cortical, but not hippocampal samples. Four week old TgCRND8 Joan Forder PhD(1), Michael Tymianski PhD, MD,(1,2). (1) Division of and non-Tg mice had equivalent levels of complex I + III and IV activities. Integrative Neurobiology, University Health Network; (2) Department of These findings reveal a coincidence between emergence of NOR deficits and Surgery, University of Toronto altered oxidative phosphorylation activity. The NOR test provides an index of the behavioural impairment associated with the early stages of Neuronal damage following stroke involves the simultaneous mitochondrial dysfunction in the TgCRND8 mouse. Supported by OMHF overproduction of nitric oxide and superoxide leading to formation of and OGSST (Paul and Adelle Deacon graduate scholarship). peroxynitrite. Peroxynitrite results in nitration of tyrosine residues. We hypothesized that small amounts of peroxynitrite will protect neurons from oxygen/glucose deprivation and translates to a neuroprotective role in vivo. 138 A126 To determine the timeline of nitrotyrosine (NT) formation following stroke, THE INFLUENCE OF AGE AT THE TIME OF INJURY ON we measured its levels in tissue homogenates from ipsi- and contralateral MORTALITY, NEUROLOGICAL RECOVERY AND AXONAL hemispheres of animals subjected to stroke at various times following SURVIVAL AFTER ACUTE TRAUMATIC SPINAL CORD INJURY permanent focal ischemia. Here we report that NT expression precedes Julio C. Furlan, M.D., M.B.A., M.Sc., Ph.D.(1,); Michael B. Bracken M.D. infarct development in stroke animals and is located exclusively within the (2); Michael G. Fehlings M.D., Ph.D., F.R.C.S.C., F.A.C.S.(1). (1) Krembil cytoplasm of neurons. To further elucidate the proteins nitrated in stroke, Neuroscience Centre, Spinal Program, Toronto Western Hospital, University immunoprecipitation was performed and then analysed by LC-ESI/MS/MS. Health Network and Department of Surgery, Division of Neurosurgery, We analysed the protein content of three distinct bands in the University of Toronto; (2) Center for Perinatal, Pediatric and Environmental immunoprecipitates of protein lysates from strokes that were not present in Epidemiology, Yale University, New Haven, Connecticut lysates taken from control brains (~30, 70, and 100 kDa). The detected proteins were categorised as being involved in either synaptic vesicle The incidence of spinal cord injury (SCI) is rising in the elderly due to trafficking/docking (Ap2 Complex, Synapsin, Dynamin, AP180, Tubulin), changing population demographics with the aging of an active “baby-boomer metabolism (ex. H+ transporting, ATPase; GAPDH; 3-oxoacidic CoA generation”. This study examines the potential age-related differences on Transferase 1; Triosephosphate Isomerase I), or cell signalling (ex. Na/K outcome and axonal preservation following SCI. A cohort study included all ATPase, PKC). Our results indicate that NT is generated in neurons within patients who were enrolled in one of the NASCIS-2 trial groups: (i) placebo, the infarct region of a stroke in a time dependant manner, suggesting that a (ii) methypredinosolone (MPSS), and (iii) naloxone. Also, a molecular and window may exist for therapeutic intervention. Further investigation cellular examination of postmortem spinal cord tissue was performed in revealed that nitration of tyrosine residues on proteins at the synapse may individuals with cervical SCI and controls. Using NF200 immunostaining, provide a neuroprotective response to ischemia. Identification of the specific the number of axons within the corticospinal tracts, dorsal column, and pathways involved may lead to novel therapeutic innovations. descending vasomotor pathways were quantitated. In alternate sections stained for myelin, the extent of degeneration was quantitated. In the cohort, there were 171 patients in the placebo group (145 M, 26 F; ages from 13 to 137 A125 89 years), 162 patients in the MPSS group (140 M, 22 F; ages from 13 to 88 EARLY OBJECT RECOGNITION MEMORY DEFICITS AND years), and 154 patients in the naloxone group (124 M, 30 F, ages from 14 to MITOCHONDRIAL DYSFUNCTION IN APP-TRANSGENIC 86 years). In the univariate and multivariate analyses, age was not :TGGCRND8” MICE significantly associated with motor and sensory scores assessed at 6 weeks, Beverly M. Francis* 1, 2, John H. Kim 1,2, Saurabh Gupta 7, Stephan at 6 months and at 1 year post-SCI. Elderly individuals (65 years of age or Fraenkl 4,5,8, Meredith E. Barakat 1,4, Mary Maj 7, Yeni Yucel 4,5,8, Brian older) had significantly greater mortality rates at 30 days (25% versus 2.65%, Robinson 6,7, JoAnne McLaurin 1,4 and Howard T.J. Mount 1,2,3.. Centre respectively; p<0.0001), at 6 month (43.75% versus 4.19%, respectively; for Research in Neurodegenerative Diseases 1, Departments of Physiology 2, p<0.0001) and at 1 year post-SCI (46.88% versus 4.86%, respectively; Medicine 3, Laboratory Medicine & Pathobiology 4, Ophthalmology & p<0.0001) than younger individuals after traumatic SCI. The Vision Sciences 5 and Biochemistry 6 University of Toronto, Hospital for Sick immunohistology included 7 SCI cases and 5 controls with comparable age Children 7, and St. Michael’s and sex distribution. In controls, the number of axons within spinal tracts was

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not significantly correlated with age. There were no significant age-related demonstrated that deltorphin, 72h after CFA injection, induces a peak differences for extent of degeneration or for number of preserved axons antihyperalgesic effect 15 min after injection. Acute tolerance was first tested within the spinal tracts post-SCI. Our results indicate that age at time of following two consecutive injections of deltorphin. Pain behaviors were injury is not significantly correlated with motor and sensory recovery post- examined 0 to 60 min following deltorphin injection, using the plantar test SCI. Axonal survival within selected spinal cord tracts was unaffected by age (Hargreaves test). To test for chronic tolerance, we injected deltorphin twice after cervical SCI. Elderly individuals were more susceptible to death within a day (i.e. once every 12h). 72h after CFA injection, deltorphin was injected the first year post-SCI. Given this, we advocate individualizing treatment intrathecally and pain behaviors were examined using the plantar test approaches for elderly patients with SCI, as the opportunity exists for (Hargreaves test). Development of new therapies for the treatment of chronic neurological recovery in this patient group. pain is essential. Recent findings suggest that medications acting on DOR may represent a good alternative to commonly used opioids.

139 A127 THE DEGENERATIVE EFFECTS OF NEUROINFLAMMATION IN 141 A129 THE SUBSTANTIA NIGRA PARS COMPACTA: ROLE FOR GENE EXPRESSION PROFILES OF ACTIVATED MACROPHAGES NEUROPROTECTION OR NEUROTOXICITY IN PARKINSON’S IN THE CNS DISEASE Nader Ghasemlou and Samuel David. McGill University Health Centre Gandhi, Anusha;* Mangano, Emily; Hayley Shawn. Institute of Research Institute, Centre for Research in Neuroscience Neuroscience, Carleton University, Ottawa Activated macrophages in the contused spinal cord cause extensive Parkinson’s disease (PD) is characterized by loss of dopamine (DA) secondary tissue damage. However, certain conditions exist, including after neurons of the nigrostriatal pathway and corresponding disturbances of the microinjection of lysophosphatidylcholine (LPC), where macrophages in motor functioning. Accumulating evidence suggests that neuroinflammatory the spinal cord are activated and phagocytic but not cytotoxic. Understanding processes, particularly those associated with innate immune pathways, play the molecular and functional characteristics of these two types of a role in PD. In particular, pro-inflammatory cytokines, which serve as macrophages is critical in controlling the inflammatory response elicited signaling messengers of the neuroimmune axis, may orchestrate the after CNS injury. We therefore assessed the gene expression patterns of neuroinflammatory and oxidative cascades provoked in PD. For instance, macrophages isolated from the CNS at the peak of their activation after LPC tumor necrosis factor-a deficient mice were resistant to the neuro- microinjection and spinal cord contusion using Affymetrix GeneChips. degenerative effects of the DA toxin, MPTP, and we also found that mice Compared to control monocytes, there are 2354 and 2279 genes whose lacking the cytokine, interferon-g were likewise less vulnerable to this toxin. expression is changed in macrophages isolated from LPC microinjected and However, ablation of other cytokines which have some anti-inflammatory contused spinal cords, respectively (p<0.05, 2-fold change). The majority of functions, such as interleukin-6 (IL-6), actually enhanced DA loss in PD these genes are GeneOntology classified as being involved in models. Similarly, the potent anti-inflammatory cytokine, IL-10, prevented protein/receptor binding, metabolism and cytokine/cytokine receptor the damaging effects of a bacterial endotoxin upon the nigrostriatal system. interactions. When comparing the two types of activated macrophages, there Accordingly, in the present investigation we provide evidence that IL-6 and are a total of 344 genes whose expression are significantly altered (p<0.05, IL-10 may attenuate the neurodegenerative effects of combined administered 1.5-fold change). Of these, 82 genes are involved in binding, 51 in with the pesticides, paraquat + maneb that has been implicated in PD by metabolism, 28 in development and 18 in the immune response (ie: epidemiological studies. These cytokines modified the behavioral, cytokines. The most prevalent KEGG pathways are the cell adhesion neurochemical and histological pathology provoked by the environmental molecules and cytokine-cytokine receptor interactions. Of the 344 genes toxins. Ultimately, these data may provide clues as to potential inflammatory identified, over 30 were identified as potential targets to alter the cytotoxic factors that may be targeted to enhance the efficacy of clinical PD treatments. phenotype of macrophages in the CNS.

140 A128 142 A130 TREATMENT OF CHRONIC PAIN WITH A DELTA OPIOID NEUROPROTECTIVE PROPERTIES OF CYSAMINE IN ACUTE RECEPTOR SELECTIVE AGONIST VS CHRONIC MODELS OF PARKINSON’S DISEASE Hélène Beaudry, Louis Gendron. Université de Sherbrooke, Sherbrooke, Gibrat Claire, Saint-Pierre M., Rouillard C., Cicchetti F. Centre de Québec Recherche en Neurosciences, CHUL; Département de Médecine, Université Laval, Québec Opiates bind to and activate 3 classes of G protein-coupled receptors, namely mu (MOR), delta (DOR) and kappa (KOR). Although alkaloids The molecule cystamine has recently been probed for its neuroprotective activating MOR, such as morphine, are the most potent clinically used properties in Huntington’s disease, but its mechanisms of action are still analgesics, they often induce important adverse effects such as nausea, largely unknown. Since several neurodegenerative disorders may share constipation, respiratory depression or sedation. In addition to those side similar oxidative and programmed cell death, it is reasonable to think that the effects, morphine induces tolerance. For most patients, these side-effects therapeutic gain of cystamine can be observed in Parkinson’s disease (PD). dramatically reduce their quality of life. Agonists acting selectively at DOR We thus recently investigated the neuroprotective effects of cystamine in (e.g. deltorphin) have lower analgesic potency, but recent data shows that acute parkinsonian mouse model generated by the toxin MPTP. Aged mice under certain experimental conditions (e.g. inflammation) the analgesic (16 months of age) were assigned to either a low dose (10 mg/kg/day) or a potency of deltorphin can be increased. Opposing to the increase in high dose (50 mg/kg/day) of cystamine treatment beginning: 1) 2 days prior antihyperalgesic effect of deltorphin, only few side effects are observed when to systemic MPTP administration or 2) on the day of MPTP lesioning. Pre- the delta selective agonist is intrathecally administered to rats. Whether treatment with lower doses of cystamine (10 mg/kg) revealed significantly treatment of chronic pain with repeated administrations of deltorphin is increased levels of tyrosine hydroxylase (TH) striatal fiber, significant submitted to tolerance remains to be investigated. To verify if repeated increases in the number of TH-immunoreactive cells, significant increase of deltorphin treatments can induce tolerance, we used a model of chronic substantia nigra Nurr1 mRNA levels and in the number of cells expressing inflammatory pain induced by an injection of Complete Freund’s Adjuvant the dopamine transporter (DAT) as compared to MPTP treated mice. (CFA) in the plantar surface of the left hindpaw. In this model, it has been Concomitant treatments (i.e. when cystamine treatment was started at the

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same time as MPTP lesioning) displayed reduced efficacy. We are now neuronal growth during development. The albino Xenopus laevis tadpole is reporting the same neuroprotective properties of cystamine in cohort of 80 an attractive model organism as it allows for the direct imaging of neuronal young parkinsonian adult mice (generated by a systemic MPTP treatment) growth and synapse formation, in vivo, in real-time within the intact when pre-treatment with low doses of cystamine is used. We are pursuing the developing brain, using multiphoton fluorescence microscopy. Further, this investigation of the neuroprotective properties of cystamine using chronic system is readily amenable to in vivo electrophysiology and genetic administration of MPTP in mice. This 28 days intraperitoneal delivery manipulation. Bath application of the convulsant pentylenetetrazol (PTZ) to produces a more progressive degeneration of the DA system and includes the freely swimming or acutely immobilized unanaesthetized tadpoles reliably induction of nuclear inclusions not seen in the acute model. Using both of elicited behavioural and electrographic seizure activity. Seizures ceased upon these models, we intent to determine if cystamine holds neuroprotective washout of PTZ or after bath application of the anticonvulsant valproate. The properties in chronic neuronal degeneration paradigms. Given its immediate and short-term effects of PTZ-induced seizures on neuronal neuroprotective action in either or both context, treatments using cystamine growth in vivo were subsequently examined. Repeated time-lapse imaging of could be applied to different classes of PD patients. individual fluorescently labeled immature neurons in vivo revealed that prolonged PTZ-induced seizures inhibit dendritic arbor growth, eventually resulting in retraction of existing branches. Rapid time-lapse imaging during 143 B126 seizures, in immobilized unanaesthetized tadpoles, revealed that dendritic HYDROGEN PEROXIDE UPREGULATES DOPAMINE D2 filopodia – dynamic ultrastructural processes involved in arbor growth –- are RECEPTORS IN RETINOIC ACID DIFFERENTIATED SH-SY5Y significantly less motile and have a lower turnover rate compared to controls. NEUROBLASTOMA Our results strongly suggest that seizures impede neuronal growth within the Patrick Berube, Annie LaRouche, Sylvain Grignon. Sherbrooke University, developing brain. These findings are of particular clinical relevance given Departments of Physiology and Psychiatry that the observed anatomical changes likely affect neuronal function and connectivity. The striatum is exposed to high levels of oxidative stress, a fact that is often explained by locally high levels of dopamine and oxidation thereof. Moreover, H2O2 has recently been shown to act as a non conventional 145 B128 neurotransmitter at striatal synapses [1]. Little is known, however, regarding ULTRASTRUCTURAL LOCALIZATION OF DELTA OPIOID the adaptation of key components of dopaminergic neurotransmission to RECEPTORS FOLLOWING PERIPHERAL NERVE INJURY: subacute, non lethal oxidative stress. This prompted us to investigate the IMPLICATIONS FOR NOVEL PAIN TREATMENT? effects of H2O2, a canonical oxidant, on the expression levels of dopamine S.V. Holdridge*1, K. Jhamandas1,2 & C.M. Cahill1,2. Departments of receptors D2 (DRD2) and tyrosine hydroxylase (TH) in retinoic acid (RA) 1Pharmacology & Toxicology and 2Anesthesiology, Queen’s University, differentiated SH-SY5Y, an acknowledged in vitro model of dopaminergic Kingston neuron [2]. On the same model, we also tested the effect of polyinosinic- polycytidylic acid (poly (IC)), which has recently been used in preclinical Neuropathic (NP) pain is defined as pain caused by a peripheral and/or models of schizophrenia and shown to disrupt dopamine homeostasis [3]. central nervous system lesion with sensory symptoms and signs and is SH-SY5Y (ATCC) were differentiated for 6 days in the presence of 10 estimated to affect 2-3 % of the population. Despite its prevalence and microM RA and exposed for 24 h to H2O2 (100 microM) or poly(IC). DRD2 adverse impact on functionality and quality of life, it remains a significant protein levels were assessed by western blotting with ECL detection. We challenge for physicians as it is typically refractory to traditional analgesics. used quantitative real time PCR with Sybr-Green detection and beta-tubulin However, research in ours and other laboratories increasingly suggests a as a reference gene to measure DRD2 mRNA levels. Nuclear and therapeutic role for delta opioid receptor (δOR) agonists in treating NP cytoplasmic levels of NF kappa B p65 were assessed by immunoblotting pain. Following induction of NP pain in rats, δOR activation produced after cellular fractionation. After H2O2 incubation, DRD2 protein levels anti-allodynia as well as enhanced antinociception in NP rats compared to were increased (+ 59% ; p=0.012) as well as mRNA levels (+ 9% ; p=0.012). controls in two acute thermal pain paradigms, suggesting injury-induced Poly (IC) did not elicit any change. Under our conditions, H2O2 but not poly changes in δOR function. This functional enhancement does not (IC) induced nuclear translocation of NF kappa B p 65, which mimicked their appear to be a result of enhanced δOR biosynthesis, as δOR effect on DRD2 regulation. The effect was restricted to differentiated (vs protein did not significantly increase. It is therefore hypothesized that undifferentiated) SH-SY5Y. TH levels were not modified under our alternative mechanisms, such as increased cell-surface expression, may be experimental conditions. Increased striatal DRD2 binding potential has been responsible. Accordingly, we have examined δOR sub-cellular described in restless legs syndrome, Parkinson’s disease, antipsychotics side localization by electron microscopy immunohistochemistry using effects and schizophrenia, where it might be a vulnerability and prognosis immunogold labeling in the spinal cords of NP and control rats. The number marker. The present results suggest that oxidant status might be a relevant and proximity to the plasma membrane of silver-enhanced gold particles parameter in the control of DRD2 levels. 1. Avshalumov, M.V., et al. J were assessed within the dorsal horn. Preliminary data reveal a shift in Neurosci, 2005. 25(17): p. 4222-31; 2. Presgraves, S.P., et al. Neurotox Res, δOR sub-cellular compartmentalization from intracellular to 2004. 5(8): p. 579-98.; 3. Ozawa, K., et al.Biol Psychiatry, 2006. 59(6): p. membrane-bound in postsynaptic profiles within the spinal cord of NP rats. 546-54. Further studies will assess δOR sub-cellular localization at presynaptic sites as well as visualization of internalized fluorophore-tagged δOR ligand, as an index of functional δOR recruitment. The targeting of 144 B127 δORs to neuronal plasma membranes with a corresponding EXAMINING SEIZURE-INDUCED EFFECTS IN THE enhancement in antinociceptive effectiveness may represent a compensatory DEVELOPING BRAIN-A NOVEL EXPERIMENTAL MODEL mechanism by which neurons may sustain an inhibitory tone during chronic D. Sesath Hewapathirane*, Simon Chen, Wesley Yen, Kurt Haas. Brain pain states, and in turn, indicate a viable target for pharmacological Research Centre, University of British Columbia, Canada intervention.

Considering that seizures are most common during childhood, understanding the possibly detrimental effects of seizures on neuronal growth during development is highly warranted. We have developed a novel model system allowing the direct examination of seizure-induced effects on

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146 B129 148 B131 MITOFUSIN 2 PROTECTS AGAINST ACUTE NEURONAL INJURY MODELING MODEL NEURON DISORDERS IN ZEBRAFISH Arezu Jahani1, Eric C.C. Cheung1, David S. Park1, Heidi McBride2, Ruth Edor Kabashi1,2, Francois Gros-Louis3, Pierre Drapeau2 and Guy S. Slack1. 1University of Ottawa, Department of Cellular and Molecular Rouleau1. 1Centre for the Study of Brain Disease, CHUM Research, Centre, Medicine; Ottawa Health Research Institute- Neurosciences Program; Notre-Dame Hospital, Montreal; 2Universite de Montreal, Department of 2University of Ottawa Heart Institute, University of Ottawa, Ontario Pathology and Cellular Biology, Montreal; 3Universite de Laval, Quebec

Formation of a mitochondrial network would be required to maintain the Amyotrophic lateral sclerosis (ALS) is the most common motor neuron functional peripheral nerve axon. MFN2, a mitochondrial transmembrane disorder (MND) with major symptoms and death resulting from dysfunction GTPase, regulates the mitochondrial network architecture by fusion of and loss of upper and lower motor neurons. Animal models of ALS will aid mitochondria. Mfn2 plays an important role in the nervous system as point to understand the molecular mechanisms that lead to motor neuron mutations of this isoform are associated with Charcot Marie Tooth dysfunction and death and also propose new treatments for these neuropathy. Here, we investigate whether Mfn2 plays a role in the regulation neurodegenerative disorders. Recently, mutations in the vesicle-trafficking of neuronal cell death. We first examine mitochondrial dynamics following protein, vesicle associated protein B (VAPB) was found to cause two types different modes of injury in cerebellar granule neurons. We demonstrate that of MNDs, ALS and late-onset spinal muscular atrophy (SMA) most likely neurons exposed to DNA damage or oxidative stress exhibit extensive due to loss of function of the VAPB protein. We decided to develop a novel mitochondrial fission, an early event preceding neuronal loss. The extent of model of motor neuron disorder in zebrafish. The zebrafish VAPB gene is mitochondrial fragmentation and remodeling is variable and depends on the highly homologous to the human gene (77%). A specific antisense mode and the severity of the death stimuli. Expression of wild type Mfn2 and morpholino oligonucleotide (AMO) to this gene was designed to selectively a hydrolysis deficient mutant of Mfn2 Mfn2RasG12V), inhibits knock-down VAPB. Injection of this AMO in zebrafish embryos (one to eight mitochondrial fragmentation and cell death following injury. Neurons cell stage) led to a specific motor phenotype, slower swimming ability after respond with a dramatic lengthening of the mitochondria, up to 30 microns proper touch response (30-50% affected according to the dose) as well as within the processes. More importantly, while both Mfn2 and Mfn2RasG12V more generalized developmental abnormalities (30%). This response was not function equally to promote fusion and lengthening of mitochondria, the found in zebrafish embryos injected with a control mis-sense AMO. Even activated Mfn2RasG12V mutant shows a 2 fold increase in protection of though the number of motor neurons remained unchanged in fish with neurons against cell death. These findings implicate a signaling role for Mfn2 swimming deficits, abnormal guidance of motor axons and decreased firing in the regulation of apoptosis that extends beyond its role in mitochondrial intensity and frequency was measured in motor neurons of VAPB knock- fusion. down zebrafish. The motor neuron deficit was rescued when VAPB AMO was injected with human WT RNA. However, no rescue was conferred when the mutant form of VAPB RNA found in ALS was injected alongside the 147 B130 VAPB AMO. The VAPB knock-down zebrafish represents an excellent PROTEIN NITRATION CAUSES NEURONAL DEATH animal model to study the pathophysiological mechanisms and therapeutical FOLLOWING TRAUMATIC BRAIN INJURY strategies in ALS as well as other types of MNDs. Michael Jones* 1,3, Anthony Lau1,3, Hong Sun1,3, and Michael Tymianski1,2,3. Departments of Physiology1 and Surgery (Neurosurgery)2, University of Toronto, and Division of Fundamental Neurobiology3, Toronto 149 B132 Western Research Institute, Toronto APOPTOSOME FORMATION CRITICALLY MEDIATES THE INDUCTION OF PROGRAMMED CELL DEATH IN MOTOR Recently, research has focused on the role of free radicals in mediating NEURONS IN VIVO neuronal degeneration following traumatic brain injury (TBI). The reaction A.K. Kanungo1, Z. Hao2,, A.J. Elia2, T.W. Mak2, J.T. Henderson1. 1Faculty between the free radicals superoxide (O2•-) and nitric oxide (NO•) to of Pharmacy, University of Toronto. 2 The Campbell Family Institute for produce peroxynitrite (ONOO-) is required to be lethal in a secondary model Breast Cancer Research, Toronto of TBI. Additionally, inhibition of NO• production has been shown to be neuroprotective (Arundine et al., 2004). Subsequently, a whole animal model Programmed Cell Death (PCD), is a significant contributor to a variety of of TBI resulted in increased 3-nitrotyrosine (3-NT), a marker for ONOO- central nervous system (CNS) insults. Experimental efforts to directly assess (Lau et al, 2006). What remains unclear is the temporal profile of ONOO- the role of the apoptosome in mediating PCD following motor neuron injury production, and relationship between peroxynitrite and neuronal damage. in vivo have been hindered by the embryonic lethality exhibited by This was investigated using the lateral Fluid Percussion Injury (FPI) model cytochrome c, Apaf-1 and caspase-9 null mice. In order to determine the role of moderate TBI in rats. A temporal increase in protein nitration occurs in of the apoptosome in regulating injury-induced PCD, we have examined injured neurons immediately following injury, peaking at 12 hours, and motor neuron death following axotomy in mice expressing a point mutant of persisting for at least 24 hours. Injured neurons exhibit nitrated proteins in cyt c (K72A) which retains its ability to perform in oxidative the cytoplasm, have altered morphology compared to non-nitrated neurons, phosphorylation but does not bind the WD-40 repeat motifs of Apaf-1. As a and undergo neurodegeneration. Meanwhile, protein nitration was not result, cytochrome c-dependent activation of Apaf-1 is inhibited. Facial observed in astrocytes. Mass spectrometry identified several key, axotomies performed on cyt c (KA/KA) mice at postnatal day 3.5 cytoplasmic neuronal proteins as nitrated, such as GAPDH and TPI, and demonstrated a three-fold increase in the survival of motor neurons using an ex-vivo system, ONOO- was shown to inhibit GAPDH activity compared to control littermates. Elevated levels of caspase-3 activation and through cysteinyl oxidation. Taken together, our results suggest that TUNEL immunoreactivity was observed within the facial nucleus of peroxynitrite is formed rapidly following FPI, inactivates key neuronal axotomized control mice ipsilateral to the lesion by 48 hours post-axotomy, proteins, and causes neurodegeneration. but was largely absent in cyt c (KA/KA) mice. In addition, our results demonstrate that following axotomy, AIF translocation does not occur in the absence of apoptosome activity. Taken together, these results demonstrate that, downstream of the mitochondria, the apoptosome plays a dominant role in mediating motor neuron PCD following facial axotomy. Funded by the Canadian Institute for Health Research (CIHR), The Amyotrophic Lateral Sclerosis Society of Canada (ALS), and The Muscular Dystrophy Association of Canada (MDAC).

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150 B133 performed weekly starting from postnatal weeks 3-4 till the end stage of the CYCLOSPORIN A OFFERS PROTECTION AT THE ISCHEMIC disease. Loss of extension reflex, weight-loss and motor deficits were used SYNAPSE as indicators of clinical symptoms. The results were obtained from 12 B. Kavousi, C.J. Feeney, P.L. Carlen. Department of Physiology, University female/male mice matched-age littermates and were compared to adequate of Toronto controls. Data collected by in vivo imaging showed that photon emission/GFAP signal was first detected at the lumbar spinal cord area. The Ischemia and its resultant reperfusion oxidative stress, lead to immediate signal first arose from small multiple areas of astrocytes activation which and delayed synaptic dysfunction characterized by decreased evoked and then converged into a larger signal around 80-100days of age. The correlation increased spontaneous neurotransmitter release, possibly due to presynaptic analysis between live imaging and behaviour data revealed that increase in mitochondrial dysfunction. The increased intracellular Ca2+ that follows an GFAP signal in the spinal cord at 70-80 days correlated with the initial ischemic episode can reach pathological concentrations, exhausting the cell’s disease onset (loss of extension reflex). Moreover the peak signals arising buffering capabilities leading to oxidative stress. This could eventually from the spinal cord around 100 days correlated with the abrupt onset of activate the mitochondrial permeability transition pore (mPTP), sensori motor deficit and paralysis. The end-stage of the disease (approx compromising cellular energetic metabolism and synaptic transmission. 133d) was characterized by GFAP signal in the brainstem and in the brain Since blocked synaptic transmission is an early event in ischemia which and coincided with loss of body weight, suggesting distal-rostral spreading of precedes cell death, it may be a target for neuroprotection. Since the effects the disease. These mice will provide unique tools for understanding disease of ischemia vary with age, acute hippocampal slices from both young (3-6 pathology and longitudinal responses to drug testing. Acknowledgment weeks) and aged (13-16 weeks) mice were used. We found that 8 minutes of CHIR,RRTQ, FRSQ. oxygen glucose deprivation (OGD) in young control slices and 6 minutes of OGD in aged control slices were critical time points, where the decline in fEPSPs was irreversible upon oxygen and glucose reintroduction. We 152 B135 hypothesized that blocking the mPTP with cyclosporin A (CsA) during OGD NEUROMOTOR, COGNITIVE AND SYNAPTIC ANOMALIES IN would help recovery of OGD-induced failure in synaptic transmission, which α-SYNUCLEIN-TRANSGENIC MICE: A MODEL OF we believe is presynaptic in origin. To test our hypothesis, 8 minutes of OGD PARKINSON’S DISEASE DEMENTIA? in young slices and 6 minutes of OGD in aged slices were both administered J. H. Kim*1, B. Francis1, J. Lin1, T. Langman1, D. Westaway2, A. Tandon1, in the presence of CsA. As well, CsA was also present during reintroduction H. T. J. Mount1. 1CRND, Dept. Medicine and Dept. Physiology, University of glucose and oxygen. Our results showed that the addition of CsA during of Toronto, 2Division of Neurology, Dept. Medicine, University of Alberta, 8 minutes of OGD and during reperfusion, allowed for substantial recovery Edmonton of fEPSPs in young slices. Similar results were seen in the aged slices. This suggests that blocking the opening of the mtPTP can ameliorate OGD The accumulation of α-synuclein deposits is a hallmark of the induced synaptic deficits. Mitochondrial dysfunction has been observed in Parkinson’s disease (PD) brain and this accumulation may play an important the Alzheimer's disease (AD) brain. The dysfunction is characterized by role in disease pathogenesis. Synuclein aggregates in PD are concentrated in altered mitochondrial calcium buffering capabilities and the increased open brainstem nuclei, including neurons of the substantia nigra. A “PD dementia” probability of the mPTP. Thus, the AD brain might be more vulnerable to (PDD) is also observed in 40-70% of patients. The occurrence and severity ischemic insults, presumably providing a segue towards the development of of dementia may be correlated to the accumulation of α-synuclein in Vascular Dementia (VD). Subsequent experiments will examine whether the entorhinal cortex, hippocampus and amygdala. Evidence of dysfunction CsA can ameliorate OGD induced alterations in synaptic transmission in the in these areas include reports that PD patients exhibit early deficits in visual hippocampal region of a transgenic mouse model of Alzheimer’s disease. object recognition and an absence of amygdala event-related potentials in Supported by: CIHR response to fearful facial expression. We probed for PD-like neuromotor and cognitive impairments in new lines of α-synuclein transgenic mice in which the hamster prion promoter controls expression of human wild type 151 B134 (WT) or missense mutant α-synuclein (A53T and A30P) transgenes. GENERATION OF A NEW MODEL-SYSTEM TO STUDY We found progressive neuromotor deficits and gait asymmetry in adult AMYOTROPHIC LATERAL SCLEROSIS DISEASE BY NON A30P-Tg mice. The A53T-Tg was also associated with motor impairment, INVASIVE IMAGING when expressed in α-synuclein-knockout mice, suggesting that the Keller A.Florence * & Kriz Jasna. Université Laval, centre de recherche du endogenous murine protein abrogates effects of human A53T α- CHUL, Ste-Foy, Quebec synuclein expression. We observed deficits in 3 h novel object recognition memory, suggestive of entorhinal cortical and hippocampal dysfunction, in 4 Amyotrophic lateral sclerosis (ALS) is a late onset neurological disease mos old A30P-Tg and A53T-Tg mice. To test amygdala function, we characterized by progressive spinal motor neurons degeneration associated examined retention of an association between presentation of a tone and a with paralysis and eventually death. Transgenic mice expressing a mutant mild electric shock. Tone-dependent freezing was significantly impaired in sodium dismutase1 (SOD1) develop phenotype with many pathological 4 mos old A30P-Tg mice. By 8 mos, A53-Tg mice also displayed deficits in features resembling human familial and sporadic ALS. Although major fear conditioning. The constitutive activation state of stress activated protein clinical symptoms in ALS arise from neurodegeneration and death of kinase (SAPK/JNK), was examined in regionally dissected brains. Levels of motoneurons, recent studies suggest that non neuronal cells could play a role phosphorylated SAPK were dramatically upregulated in rhinal cortices, in the toxicity to motor neurons. Their precise role in onset and progression amygdala, hippocampus, and cerebellum of A53T-Tg and A30P-Tg animals. of the disease remain however unknown. To further investigate the role of Finally, levels of synaptophysin, a presynaptic marker, were lower in the non-neuronal cells in the disease onset and progression, we developed mouse hippocampus and cerebellum of animals expressing A53T, or A30P missense model for live imaging of astrogliosis in ALS. As a glial fibrilary acidic mutations. Upregulated levels of phosphorylated SAPK and reduced levels protein (GFAP) is strongly up-regulated in ALS, we used it as a hallmark of of synaptophysin suggest synaptic degeneration in the mutant animals. The astrogliosis to create our model. We crossed mice carrying the firefly pattern of behavioral, biochemical and synaptic anomalies in these mice luciferase gene under the transcriptional control of mouse GFAP promoter implicate dysfunction in entorhinal cortex, hippocampus and amygdala and (GFAP-luc, Xenogen, CA) with mice carrying the SOD1G93A mutation. The suggest that they may provide relevant models for studying mechanisms double transgenic GFAP-luc/SOD1G93A mice were used in the study as well underlying cognitive dysfunction in PDD. as GFAP(wt)-SOD1G93A and GFAP as controls. Live imaging was

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153 B136 155 B138 THE MOVEMENT CORRECTION DEFICIT IN HUNTINGTON’S EXAMINATION OF THE THERAPEUTIC EFFECT OF AN DISEASE IS SENSITIVE TO TERMINAL CONTROL ENGINEERED TRANSCRIPTION FACTOR PROMOTING REQUIREMENTS ACTIVATION OF VASCULAR ENDOTHELIAL GROWTH FACTOR Martin Lemay*,1,2, Sylvain Chouinard1, Francois Richer1. 1 Unité des IN SPINAL CORD INJURY troubles du mouvement, Centre Hospitalier de l'Université de Montréal, Y Liu1, SK Spratt2, G Lee2, D Ando2, R Surosky2 and MG Fehlings1,3,4.. Montréal. 2 Université du Québec à Montréal, Montréal 1. Cell. and Mol., Toronto Western Research Inst., 2. Therapeutic Development, Sangamo BioSciences, Pt. Richmond, CA, USA, 3. Krembil Huntington's disease (HD) is an autosomal dominant neurodegenerative Neuroscience Centre, University Health. Network, 4. Div Neurosurg, disorder affecting the striatum at early stages. HD is characterized by University of Toronto involuntary and voluntary movement deficits, cognitive decline and behavioral disturbances. Rapid pointing movements performed by patients Spinal cord injury (SCI) results in the initiation of multiple secondary are usually slower and more irregular than controls, especially in the terminal injury cascades, one of which is the disruption of spinal cord blood flow and corrective phase. The movement correction deficit in HD is still poorly the onset of spinal cord ischemia. Vascular endothelial growth factor (VEGF) understood and a better characterization of this problem could help is a prototypical angiogenic growth factor, more recent findings revealed that understand the role of fronto-striatal systems in movement. This study VEGF also has direct effects on neural cells. An engineered zinc finger examined whether the correction deficit in target acquisition is sensitive to protein (ZFP) transcription factor was designed to activate expression of all terminal control requirements or to visual attention load. We compared the isoforms of the endogenous VEGF gene for complete biological function. cyclical movements (back-and-forth pointing) to discrete pointing The aim of this study was to evaluate the effect of a recombinant adenoviral movements performed to a target surrounded or not by distractors. Sixteen vector or adeno-associated virus containing an engineered ZFP-VEGF-A patients with early HD and 16 age-matched controls participated in the study. transcriptional activator (AdV-ZFP-VEGF or AAV-ZFP-VEGF) after SCI in Reducing the termination requirements (cyclical movements) significantly adult rats. In the acute phases, the adenovirus vectors encoding either Ds-Red attenuated the correction deficit in patients as shown by a shorter and less fluorescent protein or ZFP-VEGF-A were delivered locally immediately after irregular corrective phase in cyclical movements as compared to discrete a 35g clip compression injury. In AdV-Ds-Red injected rats, adenovirus- movements. Distractors around the target affected the initial part of the infected cells were observed in gray and white matter, and the vectors movement (lower speed and movement irregularity) but did not affect the transduced neurons, astrocytes and oligodendrocytes. VEGF mRNA levels two groups differentially. These results suggest that the error correction encoding for VEGF 120, 164 and 188 isoforms were measured by real-time problem in HD is sensitive to terminal control requirements and that this PCR and VEGF protein. Neurofilament 200 protein (NF200) levels were effect is independent of visual attention. Acknowledgments: This research determined by Western blot analysis. Administration of Adv-ZFP-VEGF was supported by the Huntington’s Disease Society of America and by the resulted in an increase of VEGF mRNA and protein levels at 3 days after Natural Sciences & Engineering Research Council. injury. The posttraumatic degradation of NF200 was significantly attenuated in the ZFP-VEGF treated animals at 7 days after SCI. Expression of ZFP- VEGF-A was confirmed by Western blot. In the injured spinal cord area ten 154 B137 days after SCI and treatment, using immunohistochemistry, a significant AN IMMUNIZATION STRATEGY FOR TREATING increase in vascularization (assessed by RECA-1 immunostaining) and AMYOTROPHIC LATERAL SCLEROSIS decreased levels of apoptosis (assessed by TUNEL) occurred in rats treated Hsueh-Ning Liu, Sonja Tjostheim, Patrick Horne, Kevin Dasilva, Mary with AdV-ZFP-VEGF compared with controls. Furthermore, in the more Brown, Avijit Chakrabartty, JoAnne McLaurin, and Janice Robertson. chronic evaluation period, animals treated with AAV-ZFP-VEGF showed Center for Research for neurodegenerative Diseases, University of Toronto significant improvement in hind limb function up to six weeks after injury compared with control animals. Our finding suggests that this engineered Immunotherapy is emerging as a therapeutic approach in the ZFP-VEGF-activating transcription factor led to upregulation of VEGF neurodegenerative diseases characterized by deposition of aggregated and/or mRNA and protein, attenuation of NF200 degradation, protection/repair of misfolded protein including amyotrophic lateral sclerosis (ALS). ALS causes blood vessels, decreased apoptosis, and enhanced functional neurological progressive motor neuron degeneration in the brain and spinal cord. In outcome. These data suggest that VEGF gene therapy using a ZFP familial ALS cases harboring mutations within the gene encoding superoxide transcription factor plasmid holds promise as a therapy for SCI and other dismutase-1 (SOD1), SOD1 aggregates are found in motor neurons. forms of neurotrauma. Although the precise molecular mechanisms of motor neuron degeneration in the presence of mutant SOD1 remain to be elucidated, it is suggested that toxicity is related to the propensity of the mutant protein to misfold and/or 156 B139 dissociate from a dimer into a monomer, and ultimately to form aggregates. SHORT CHAIN FATTY ACIDS INDUCE CATECHOLAMINERGIC The in vivo presence of misfolded/monomeric SOD1 is demonstrated by the NEUROTRANSMISSION IN PC12 CELLS VIA A CREB recent development of an antibody, called SOD1-Exposed-Dimer-Interface DEPENDANT MECHANISM- POSSIBLE RELEVANCE TO (SEDI) antibody raised to an epitope that is only exposed when the AUTISM SPECTRUM DISORDERS homodimeric SOD1 is misfolded or dissociated. Here we report that an active Nankova, B,1 * MacFabe, D. F. 2 & La Gamma, E,1. 1Pediatrics, immunization strategy that selectively targets disease-associated protein Biochemistry and Molecular Biology, NY Med Coll, Maria Fareri Childrens species, misfolded/monomeric SOD1 or SOD1 aggregates, has therapeutic Hosp, Valhalla, NY USA, 2 Depts. of Psychology and Psychiatry (Division of benefits. Vaccination of ALS transgenic mice overexpressing the mutant Developmental Disabilities), Schulich School of Medicine and Dentistry, SOD1 with SEDI peptide or SOD1 aggregates delayed the onset and slowed University of Western Ontario, London the progression of disease. Immunized transgenic mice also showed a significant increase in lifespan and improvement in motor deficits. Dietary or gastroenterological factors have been implicated in autism Furthermore, accumulation of SOD1 oligomers in spinal cord extract was spectrum disorders (ASDs). Short chain fatty acids (SCFA) such as butyric reduced in vaccinated mice. These results suggest that immunotherapy (BA) or propionic acid (PPA) are present in diet or are produced by enteric effectively improves motor and pathological disease outcomes as well as bacterial fermentation of residual carbohydrates. We have shown that reduces the accumulation of SOD1 aggregates, and this therefore may intraventricular infusions of PPA can elicit consistent behavioural, provide a new means for the treatment of ALS. electrophysiological, neuropathological and biochemical effects reminiscent

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of ASD’s in rodents (MacFabe et al. 2006). Effects include activation of 158 B141 CREB dependent pathways, important in neurodevelopment, learning and STRESS AND GLUCOCORTICOIDS ACCELERATE memory. Furthermore BA can induce tyrosine hydroxylase gene expression DOPAMINERGIC CELL DEATH AND EXAGGERATE MOTOR (TH; rate limiting enzyme in biosynthesis of monoamine transmitters SYMPTOMS IN A RAT MODEL OF PARKINSON’S DISEASE dopamine, epinephrine and norepinephrine) in a PC12 cell model (Santosh Gerlinde A. Metz, Nafisa M. Jadavji, Keri L. Colwell, S. Katrina Perehudoff, 2006). Since increased monoamine concentration is known to be elevated in Lori K. Smith. Canadian Centre for Behavioural Neuroscience, University of the brain and blood of ASD patients and a number of models (Narita 2002), Lethbridge, Lethbridge we hypothesized that SCFA’s may directly influence brain catecholaminergic pathways. To determine whether SCFA’s with known behavioral effects and Stress has been one of the earliest proposed causes of Parkinson’s putative links to ASD’s (PPA; valproate, VPA) can regulate TH gene disease. The purpose of this study was to investigate if chronic stress and expression site-directed mutagenesis was used to introduce point and elevated levels of the stress hormone corticosterone exaggerate motor deletion mutations into the wild-type TH promoter driving the expression of deficits and neurodegenerative events in a rat model of Parkinson’s disease. luciferase reporter gene. After transfection and treatment with SCFA, PC12 Rats were tested in a comprehensive test battery of skilled and non-skilled cells were harvested and reporter activity measured along with endogenous movement while being exposed to daily restraint stress or corticosterone TH mRNA and TH protein. We found SB, PPA & VPA induced TH promoter treatment. Stress and corticosterone compromised normal motor function and over a wide concentration range. The canonical CRE motif the novel BRE exaggerated motor deficits caused by a dopamine depletion induced by (butyrate response element, Patel et al., 2005 and CREB transcription factors unilateral 6-hydroxydopamine infusion into the nigrostriatal bundle. were found necessary for the transcriptional activation of TH gene by all Evaluation of drug-induced rotation and immunohistochemistry indicated SCFA tested. Physiologically relevant concentrations of SCFA also caused that greater motor impairments in stress-treated animals were related to accumulation of TH mRNA and immunoreactive protein. Intraventricular accelerated death of midbrain dopaminergic neurons during the first week infusions of SB produced behavioral and neuropathological changes similar post-lesion. In addition, the lesioned substantia nigra of stress-treated to those evoked by PPA (MacFabe, 2006). In conclusion, our data are animals revealed elevated levels of glial fibrillary acidic protein indicating consistent with a molecular mechanism through which environmental signals increased reactive gliosis. These findings suggest that stress and elevated such as fatty acids can modulate animal behavior through effects on central stress hormone levels represent key factors in the pathogenesis of catecholaminergic and CREB dependant systems and are consistent with Parkinson’s disease that lead to earlier onset of symptoms and exaggerated their hypothetical role in ASDs. (Support: Mead Johnson, GoodLife neurodegenerative processes. This research was supported by: National Children’s Charities) Institutes of Health (NINDS), Parkinson’s Disease Foundation, Alberta Heritage Foundation for Medical Research. 157 B140 THE FATE OF THE LARGE STRIATAL INTERNEURONS 159 B142 EXPRESSING CALRETININ IN HUNTINGTON’S DISEASE THE IL-10 AND IL-10 RECEPTOR 1 GENES AND CHILDHOOD- *Massouh, M and Parent, A. Centre de Recherche Université Laval Robert- ONSET MOOD DISORDERS Giffard VL Misener(1), L Gomez(1), KG Wigg(1), N King(2), A Vetro(3), E Kiss(3), Z Tamas(4), JL Kennedy(2), M Kovacs(5), CL Barr(1,6), and The The severe atrophy of the striatum that characterizes Huntington's disease International Consortium for Childhood-Onset Mood Disorders. (1)Toronto (HD) is due to massive losses of striatal medium spiny projection neurons. In Western Research Institute, Toronto, (2)Neurogenetics Section, Centre for contrast, interneurons are relatively spared in HD, but little is known of the Addiction and Mental Health, Toronto, (3)Department for Child and fate of the large interneurons that express calretinin (CR) in HD. We Adolescent Psychiatry, Szeged University, Szeged, Hungary, (4)Vadaskert addressed this issue by applying a double immunofluorescent labeling Hospital, Budapest, Hungary, (5)School of Medicine, University of technique to postmortem material obtained from HD patients and age- Pittsburgh, Pittsburgh, PA, USA, (6)Brain and Behaviour Program, Hospital matched controls. Antibodies against CR and choline acetyltransferase for Sick Children, Toronto (ChAT) were used to compare the distribution, density and degree of ChAT co-localization of the CR+ striatal interneurons in normal and HD cases. The IL-10 is a pleiotropic cytokine that regulates neuronal, neuroimmune and normal human striatum was found to contain 3 types of large interneurons: a) neuroendocrine substrates implicated in the etiology of depression, such as neurons expressing CR only; b) neurons displaying ChAT only; and c) inflammatory cytokines, the HPA axis, and indoleamine 2,3-dioxygenase, an neurons co-expressing CR and ChAT. The CR+/ChAT+ neurons enzyme which limits serotonin availability. Accordingly, it is hypothesized outnumbered neurons expressing ChAT only, which were themselves more that IL-10 signalling pathway genes may be involved in genetic susceptibility numerous than neurons displaying CR only. A two-fold decrease in the to depressive disorders. Here, in a family-based association study of density of CR+/ChAT+, CR-/ChAT+ occurred in the striatum of HD patients childhood-onset mood disorders (COMD) (characterized by onset of compared to that of controls, suggesting that these neurons are affected in depression before age 15), we have begun to test this hypothesis through an HD. However, studies undertaken with neurokinine-1 receptor NK-1R as a investigation of single nucleotide polymorphisms in the gene for IL-10 marker of large CR+ and ChAT+ neurons revealed that these striatal neurons (IL10) and the gene for a component of its receptor, IL-10 receptor 1 are selectively spared in HD patients. Hence, the apparent decrease in the (IL10RA). Using a sample of 386 families (386 COMD probands, 76 number of CR+/ChAT+, CR-/ChAT+ neurons in HD does not appear to result affected siblings, and their parents), we have analysed 3 functional promoter from a degeneration of these cells, but rather from a marked diminution of variants of IL10 (-1082G/A, -819C/T, and -592C/A), and 6 polymorphisms the expression of CR and ChAT. Our data indicate that the neurodegenerative across IL10RA, including 3 coding variants (Ser138Gly, Gly330Arg, and processes at play in HD affect the expression of CR and ChAT proteins Ser399Leu) that may alter receptor function. Genetic association analyses without causing the death of these large striatal interneurons. were carried out using the transmission/disequilibrium test (TDT), testing for biased transmission of alleles from heterozygous parents to their affected offspring. TDT analysis of the IL10 gene showed no evidence for biased transmission of the promoter polymorphisms, either individually or as haplotypes. By contrast, TDT analysis of the IL10RA gene showed significant evidence for biased transmission of one of the polymorphisms (rs9610: chi-sqared=4.173;p=0.041) and for excess transmission of one of

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the 6-marker haplotypes (chi-squared=7.090;p=0.008). These findings propanol, sodium acetate or PBS vehicle (0.1M) twice daily for 5 treatment suggest the possibility of IL0RA involvement in genetic risk for depression days. Immediately following microinfusion, animals were individually and warrant further investigation. Follow-up analyses, including analyses of placed into an automated open field (Versamax) and a variety of locomotor an additional 200 newly recruited COMD families, are underway. activity variables were assessed for 30min. Afterwards, animals were sacrificed and the dorsal hippocampal foramation and adjacent white matter examined mmunohistochemically for markers of innate neuroinflammation. 160 B143 Rodents which were infused with with PPA, and to a lesser extent acetate, LONG-TERM EFFECT OF SUBCHRONIC ADMINISTRATION OF showed significant increases in locomotor activity and turning behaviour, (±) 3,4 - METHYLENEDIOXYMETHAMPHETAMINE (MDMA) ON compared to controls. Immunohistochemical analyses of brain revealed SENSORIMOTOR GATING IN RATS increased reactive astrogliosis (GFAP) and microglial activation (CD68) Daniela Mohr1,2*, Markus Fendt1,3 and Andreas Mayerhofer2. only in PPA treated animals, reminiscent of neuropathological changes found 1Tierphysiologie, Zoologisches Institut, Fakultät für Biologie, Universität in ASD autopsy tissue. PPA was not directly neurotoxic, as measured by Tübingen, Auf der Morgenstelle 28E, D-72076 Tübingen, Germany, 2 direct cell pyramidal cell counts and apoptosis ( cleaved Caspase 3). Only Neuropharmakologie, Zoologisches Institut, Abteilung Neuropharmak- PPA infusions produced behavioural and neuroinflammatory effects in rats ologie, Fakultät für Biologie, Universität Tübingen, Germany; 3 Novartis reminiscent of ASDs, suggesting a specific short chain fatty acid/pH Institutes for BioMedical Researchm Basel, Switzerland dependent effect of this compound, which may involve pH dependent activation of a number of second messenger processes, including Prepulse inhibition (PPI) of acoustic startle is the unlearned suppression intracellular calcium release and closure of gap junctions. PPA infusions in of the acoustic startle response triggered by a weak, non-startling stimulus rats may model some aspects of ASDs, and may provide a plausible which precedes the startle eliciting stimulus (pulse) by 30-500 ms. PPI has dietary/gut/CNS link to this disorder. Sponsor: GoodLife Children’s been found to be reduced in schizophrenia patients and therefore, it is an Charities operational measure of sensorimotor gating. (±)3,4-Methylenedioxymethamphetamine (MDMA, "ecstasy") is known to induce psychopathological effects in humans. MDMA acts as an indirect 162 B145 monoaminergic agonist and moreover, it is one of the most popular SEX AND AGE DEPENDENT MODULATION OF PLASTICITY IN recreational drugs. In this study we investigated the long-term effect of A MURINE MODEL OF ALZHEIMER’S DISEASE AS REVEALED MDMA on PPI in rats to prove the hypothesis of long-term psychotic events BY SYNAPTIC ZINC after MDMA consumption. Therefore, rats were treated over ten consecutive Amy S. Nakashima (1) and Richard H. Dyck (1,2,3) Departments of days with 20mg/kg MDMA or placebo. Two weeks after the treatment Psychology (1), and Cell Biology and Anatomy (2), and the Hotchkiss Brain period, behavioural testing with different prepulse intensities was followed. Institute (3), University of Calgary, Calgary In addition to the behavioural experiments, a quantification of brain monoamines was carried out via high pressure liquid chromatography Most synaptic zinc within the brain is localized within a subset of (HPLC). We observed that (1) MDMA significantly decreased PPI but does glutamatergic neurons. Once released, this zinc can modulate the activation not affect baseline startle magnitude and that (2) even weeks after MDMA of a multitude of receptors and therefore potently modulate synaptic treatment HPLC revealed a significant reduction of the content of serotonin plasticity. In addition, zinc has robust effects in a number of disease states, and its metabolite 5-HIAA in several brain areas known to be involved in PPI including Alzheimer’s disease (AD). Zinc promotes the aggregation of beta modulation. Furthermore, neither the dopamine level nor the DOPAC, HVA amyloid and the pharmacological or genetic removal of zinc leads to an or MT levels were affected. Preliminary results of a parallel experiment also amelioration of AD related pathology. As well, the increased susceptibility of show (3) a profound reduction of PPI in the acute state one hour after the females to greater pathological loads is eliminated with the genetic removal injection of 20 mg/kg MDMA. of zinc. As in mouse models of Alzheimer’s disease, deficits in plasticity are among the first features to be observed, we hypothesized that sex dependent deficits in plasticity would be revealed by synaptic zinc. Our laboratory has 161 B144 previously shown that in response to sensory deprivation, a condition in PROPIONIC ACID BUT NOT CONTROL COMPOUNDS INDUCE which endogenous plastic mechanisms are activated, a rapid, age-dependent INCREASED LOCOMOTOR ACTIVITY AND INNATE increase in synaptic zinc occurs. Using this model, we utilized male and NEUROINFLAMMATORY CHANGES IN RATS FOLLOWING female 3xTg-AD mice (1, 3, 6, 9, 12,18 months) and age-matched C57BL/6 VENTRICULAR INFUSION- A NOVEL ANIMAL MODEL FOR male and female controls. Mice were killed 48 hours following the bilateral AUTISM SPECTRUM DISORDERS removal of the c-row of vibrissae. The brains were then processed and Hoffman, J.E. , Taylor, R., * Mohammad Asef, Y., Boon, F., Cain, D.P., stained using the Timm-Danscher method in order to visualize vesicular zinc Kavaliers, M. Ossenkopp, K.P., MacFabe, D.F.,. The Kilee Patchell-Evans levels in the S1 cortex. Measures consisted of comparing the staining Autism Research Group, Departments of Psychology/Psychiatry, The intensities of the deprived row of barrels to the adjacent, non-deprived rows. Schulich School of Medicine & Dentistry. The University of Western Ontario, Four major results were observed. First, in all groups, plasticity was observed London in the form of an increase in vesicular zinc in the deprived barrels. Second, in both sexes and strains, an age-dependent reduction in plasticity was Dietary, digestive system and immunological factors have been observed. Third, female control mice had a greater plastic response implicated in the cause and symptoms of autism spectrum disorders (ASDs). compared to male control mice between three and twelve months of age Propionic acid (PPA) is a short chain fatty acid, a product of enteric bacteria, while male and female 3xTg-AD did not significantly differ from each other and a common food preservative. PPA has widespread effects on cellular at any age. Fourth, male 3xTg-AD mice consistently had an increased plastic metabolism, neurotransmitter release, second messenger signalling, response than control male mice whereas female 3xTg-AD mice had intracellular pH, and immune function. We found PPA can elicit consistent decreased plasticity at younger ages compared to female controls. These behavioural, biochemical and neuropathological changes in rodents and may findings demonstrate the complexity of the role of zinc in plasticity and AD. be an animal model for ASDs. To examine the effects of chronic They also suggest that plasticity revealed by synaptic zinc in the non- intraventricular infusions of PPA and structurally similar compounds in pathological state is sex-dependent and that this effect is altered in 3xTg-AD rodents on motor output and neuropathology, adult rats received mice. Supported by: NSERC, Scottish Rite Charitable Foundation intraventricular infusions of pH 7.5 buffered PPA (500ug/ul), isomolar 1-

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163 B146 32.6%. It was found that there was significant association between CORTICAL AND THALAMIC COMPONENTS OF NEOCORTICAL knowledge of AED and adherence to therapy (p=.00385) and there was no KINDLING-INDUCED EPILEPTOGENESIS IN BEHAVING CATS significance association between age (p=0.067), sex (p=0.182) educational Dragos A. Nita*, Youssouf Cisse, Igor Timofeev. Centre de Recherche status (p = 0.688), income (p=0.519) religion (p=0.69), place of residence Universite Laval Robert-Giffard, 2601, Ch. de la Canardiere, Quebec (p=0.157) with AED adherence. The reasons for non-adherence were as a result of forgetfulness and AED fatigue and being away from home. The neocortical kindling in the majority of cases exhibits a resistance to Adherence to AED was low despite high level of knowledge due to produce generalized convulsive seizures compared to other brain structures, forgetfulness, fatigue and being away from home, therefore a need for and therefore, it is rather difficult to use it to study the cortical mounting adherence counseling in the clinic and health educational epileptogenesis. Here, using a new method of supra-threshold cortical interventions to improve adherence in our rural communities where the kindling, we report electrophysiological patterns of synchronization of field disease cannot be managed. Further exploration of the relationship between EEG (cortical areas 4, 5, 7, 21, 17, 18, 22 & thalamic VPL nucleus); and clinical outcomes and other non-drug self-management strategies is needed. intracellular activities (area 5) in chronically implanted non-anesthetized cats, both during different states of vigilance: wake, slow-wave sleep (SWS) and rapid eye movement sleep (REM); and during acute seizures elicited by 165 B148 prolonged (20-60 s) electrical stimulation of high intensity (0.5-1.5 mA). The Laser microdissection and gene expression in striosomes and matrix highest probability to elicit paroxysmal afterdischarges was during transition compartments of the striatum in normal and Parkinsonian rats from SWS to wake. The acute elicited seizures were mainly clonic *Rémy Parent, Martin Lévesque, André Parent;. Anat & Physiology Dept, accompanied with tonic components followed by prolonged postictal Laval University, Québec depression. Delayed rhythmic outlasting activities (OA) at ~1.5 Hz followed the postictal depression and lasted up to 2 hours. These activities were clear The striatum is the main input structure of the basal ganglia; it receives during wake, slightly reduced during SWS and completely absent during major projections from the cerebral cortex, thalamus and substantia nigra. REM sleep. They started focally in the vicinity of the stimulating electrode The nigrostriatal projection uses dopamine as a neurotransmitter and its and generalized over the whole cortical surface following serial stimulation. terminal fields in the striatum conform to the two major striatal Intracellular correlates of OAs consisted in neuronal discharges during the compartments, that is, the striosomes (or patches) and the extrastriosomal depth-negative spike of the OA, but the hyperpolarizing components were matrix. These two striatal compartments differ from one another by their not accompanied by a profound hyperpolarization as during SWS and neurochemical makeup as well as by their afferent and efferent connections. neuronal action potentials were built on the summation of successive The aim of the present study was to obtain a global picture of the different synaptic FPPs. During seizures cortical activities were leading over thalamic genes expressed at the level of each of these two striatal compartments and ones, while during OA thalamic components preceded the cortical ones. to document possible changes in gene expression at these levels consecutive Electrical stimulation of locus coeruleus or pedunculo-pontine tegmentum to dopamine denervation of the striatum. Experiments were performed in during OA slightly decreased their amplitude, but was not able to completely normal rats as well as in rats in which the nigrostriatal dopaminergic pathway abolish the OA. The results suggest that such rhythmic long lasting was lesioned with 6-OH-DA on one side of the brain. The rats were first oscillatory activity outlasting seizures are the key factor of epileptogenesis, perfused during 1 minute with a phosphate buffer solution containing 30% leading to epilepsy. Supported by CIHR and NSERC. sucrose and their brain immediately frozen in liquid nitrogen. Brains were sectioned at 16 µm with a cryostat and the sections containing the striatum were collected on membrane-coated slides and fixed 10 min at -20 C in 95% 164 B147 ethanol-5% acetic acid. The sections then went though a rapid (20 minutes) EVALUATION OF FACTORS INFLUENCING MEDICATION immunostaining procedure to reveal striosomes, which are markedly ADHERENCE IN PATIENTS WITH EPILEPSY IN RURAL enriched in µm-opiate receptors. The sections were sequentially incubated COMMUNITIES OF KADUNA STATE, NIGERIA with: (1) µm-opiate receptor primary antibody during 10 minutes; (2) Ogboi Sonny Johnbull1, Sabitu K1, Idrsi S1, Farounbi B2. 1Dept. of biotinylated anti-rabbit secondary antibody during 4 minutes; (3) avidin- Community Medicine, Faculty of Medicine, Ahmadu Bello University, Zaria, biotin-peroxydase during 3 minutes; and finally (4) with DAB for 3 minutes. Nigeria. 2General Outpatient Dept, Ahmadu Bello University, Teaching Striosomes and matrix compartments were dissected out with the help of a Hospital Zaria, Nigeria/Jicon Hospital, Kaduna, Nigeria laser microdissection system (Leica AS LMD) and all portions of each striatal compartment on each section were collected in separated tubes. The Adherence to medication is the backbone to effectiveness of a therapy. In RNA was then extracted and its quality assessed with an Aligent Bio- the absence of a definitive curative therapy, antiepileptic therapy is a key Analyzer. High quality RNA samples were then amplified and hybridized to intervention aimed at prolonging and improving the quality of life of rat complete genome cDNA arrays. The data obtained in control and in 6- epileptic patients suffering from a disease known for its stigmatization with OHDA lesioned rats are likely to shed a new light on the role of the striatal many cultural misconception. The aim of the study is to assess the level of, compartmentation in both normal and pathological conditions. It is hope that and factors influencing adherence to antiepileptic therapy among patients in this approach will help identifying new avenues for the development of rural communities attending outpatient clinic in Ahmadu Bello University effective drugs to treat Parkinsonian disease. Teaching Hospital, Zaria and Jicon Hospital, Kaduna, northern Nigeria. A cross sectional descriptive study design was used. Interviewer-administered, structured questionnaires were administered to a sample of 272 epileptic 166 B149 patients attending Ahmadu Bello University Teaching Hospital/Jicon NORMAL AND ABNORMAL AGING ASSESSED USING Hospital Kaduna, who had been on antiepileptic drug (AED) for at least one OCULOMOTOR TASKS AND TESTS OF FRONTAL FUNCTION year. Systematic random sampling technique was used to select the patients. Peltsch, A.J.,1 Hemraj, A.,1 Garcia, A.,1,3 Munoz, D.P.1,2. Centre for Information was obtained on their knowledge of epilepsy and antiepileptic Neuroscience Studies1, Departments of Physiology2, and Medicine3, therapy regimen adherence to AED and factors influencing the adherence to Queen’s University, Kingston AED regimen. The level of knowledge of epilepsy, signs and symptoms was high of about 57.8%, 25.9% which had excellent knowledge and good Alzheimer’s disease (AD) is a neurodegenerative disease initially knowledge respectively. The level of antiepileptic therapy was high with characterized by progressive memory loss and cognitive deterioration, often 78.6% having excellent knowledge. The level of adherence to AED was non-differentiable from the normal cognitive decline associated with aging and Mild Cognitive Impairment of the amnesic type (MCI). MCI is an

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isolated memory deficit with normal scores in all other areas of cognition and organelles are distributed along the entire length of the axons and are normal daily function. Approximately 10% per year will go on to develop the transported in anterograde and retrograde directions. However some subtle symptoms of AD. The distinction between AD and MCI patient groups needs changes are observed, such as a significant modification of the mean velocity to be examined to determine if there are predictors of the conversion from of transport in some mice. Moreover, the protein analysis shows that the MCI to AD. We compared the ability of 77 normal elderly, 14 AD, and 19 levels of some proteins involved in axonal transport are modified. These MCI patients to perform two saccadic eye movement tasks: a pro-saccade results suggest that the modifications of the neuronal cytoskeleton analyzed task (automatically look towards a target) and an anti-saccade task (inhibit here have a moderate effect on mitochondrial and lysosomal axonal transport the automatic response and instead initiate a voluntary saccade away from in DRG neurons in vitro. the target). In healthy aging, saccadic function decreased with aging (60-90 yrs), such that subjects became slower and performed with a higher proportion of errors in the anti-saccade task (i.e. initiated erroneous pro- 168 B151 saccades). We hypothesized that AD and MCI saccade performance would TASK-RELATED PUPILLARY ACTIVATION IN HUNTINGTON’S also decline with age, but in such a way that both patient groups should DISEASE exhibit more severe impairments relative to controls. We also predicted that Maxime Philibert*, Martin Lemay, Nadera Djerroud, Sylvain Chouinard & a measurable discrepancy would exist between these two populations. François Richer. Centre Hospitalier de l’Université de Montréal, Université Saccadic reaction times (SRT) were much more variable amongst both AD du Québec à Montréal and MCI patient groups relative to controls. On anti-saccade trials, the occurrence of direction errors was higher in AD and MCI suggesting an Huntington’s disease (HD) is an autosomal dominant neurodegenerative impaired ability to inhibit automatic visually-triggered saccades, and thus disease characterized by cognitive decline, slowing of voluntary movements, decreased cognitive control. Furthermore, the variability in SRT and the choreiform movements and affective disturbances. Most HD symptoms are proportion of short-latency saccades differed between MCI and AD groups. believed to be a consequence of neuronal depletion of the striatum. In two The increased error rates and variability in SRT also correlated with altered studies we use task-related pupillary responses during auditory reaction time cognitive functions, as assessed by various psychometric tests (i.e. Stroop, tasks to explicitly examine attentional processes in patients in the early stages Wisconsin Card Sorting Test). These data provide insight into how the of HD and age-matched controls. Pupil size was measured with a head- normal and abnormal aging processes differentially affect the neural circuitry mounted infrared camera. In a first study, participants had to make rapid controlling saccade initiation and saccade suppression. This also allows us to keypress responses after hearing letters A or B presented as singletons explore potential brain changes in healthy aging, and how they relate to the (simple responses) or triplets (sequential responses). In a second study, a dysfunction in AD and MCI. Moreover, using quantitative saccade measures third condition was added where patients had to inverse their keypress in combination with neuropsychological assessment may allow us the responses (inverted simple responses), adding attentional load to the task. opportunity to differentiate the two disorders. Our results show that patients were slower and made more errors in inverted and sequential responses than controls. There was no difference between groups in baseline pupil size. However, the amplitude of the pupillary 167 B150 response was smaller in HD patients than in controls and it also increased ANALYSIS OF MITOCHONDRIAL AND LYSOSOMAL AXONAL less with task difficulty. These results suggest that HD affects the recruitment TRANSPORTS IN CULTURED DRG NEURONS WITH VARIOUS of brainstem activation systems in relation to task demands. This research NEURONAL CYTOSKELETON DISORGANIZATIONS was supported in part by grants from the Canadian Institutes of Health Rodolphe Perrot*, Jean-Pierre Julien. Department of Anatomy and Research and the Huntington's Disease Society of America. Physiology, Laval University, Research Centre of CHUL, Quebec

Abnormal accumulations of intermediate filaments (IFs) are a 169 B152 pathological hallmark of many human neurodegenerative disorders including EFFECTS OF CHRONIC BUPRENORPHINE TREATMENT ON amyotrophic lateral sclerosis, Parkinson’s disease, Charcot-Marie-Tooth and LEVELS OF NUCLEUS ACCUMBENS DOPAMINE AND giant axonal neuropathy. Several studies provided evidence that GLUTAMATE IN COCAINE-SENSITIZED AND NON-SENSITIZED disorganization of the neuronal IF network may be directly involved in RATS neurodegeneration. However, the exact molecular mechanisms underlying F.M. Placenza *, H. Rajabi, J. Stewart. Center for Studies in Behavioral the deleterious effects of IFs disorganization remain elusive. We postulate Neurobiology, Concordia University, Montreal that changes in the organization of IFs can influence the fast axonal transport machinery either through levels of motor proteins or block of cargoe Buprenorphine (BUP) is a partial mu-opioid receptor agonist currently movement. To test this hypothesis, we analyzed the axonal transport of being used as a maintenance treatment for opiate dependence. Previous work mitochondria and lysosomes in cultured dorsal root ganglion (DRG) neurons in our lab has shown that in rats with a history of cocaine self-administration, from different mouse models with various abnormalities of the neuronal chronic BUP treatment prevents the reinstatement of cocaine seeking by a cytoskeleton, including NFL knockout mice, which are characterized by the priming injection of cocaine and reduces cocaine self-administration, but absence of axonal neurofilaments, gigaxonin-deficient mice, which develop potentiates the nucleus accumbens (NAc) dopamine (DA) response to an IF accumulation in specific region of the nervous system, mice acute injection of cocaine. In a continuing effort to understand the effects of overexpressing peripherin (Per mice) that develop a motor neuron disease BUP on responses to cocaine, we investigated the effects of chronic BUP characterized by the presence of IF inclusions, and finally Per NFL-/- mice treatment on NAc DA levels and on locomotor activity in rats pre-exposed to in which the onset of peripherin-mediated disease is precipitated. We used repeated injections of cocaine. Given previous reports showing that basal time-lapse microscopy to measure the movement of mitochondria and levels of glutamate (GLU) in the NAc are reduced after repeated exposure to lysosomes in cultured DRG neurons after staining with respectively cocaine, we also examined the effects of chronic BUP treatment on NAc MitoTracker Red CMX-Ros and LysoTracker Red DND-99. We also GLU levels. Male Long Evans rats were given daily injections of cocaine or analyzed by Western-Blot the expression of proteins involved in axonal saline for 7 days. On days 1 and 7, cocaine (15 mg/kg; i.p.) or saline was transport (KIF1A, KIF5A, dynein, NUDEL and p150glued) in the sciatic given in the testing environment; on days 2-6, cocaine (30 mg/kg; i.p.) or nerve and in the optic nerve from the different mice. Preliminary results saline was given in the home cage. Following an 18-20 day withdrawal indicate that these alterations of the neuronal cytoskeleton induce no major period, rats had BUP-containing osmotic minipumps (3 mg/kg/day) modifications of the mitochondrial and lysosomal axonal transport. These surgically implanted, or underwent sham surgery. Three days later, all rats

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were brought to the testing environment where locomotor activity was and long-term survival, migration, differentiation and axonal outgrowth of monitored and extracellular levels of NAc DA were assessed using in vivo neurospheres transplanted into the mouse brain. Cortex-derived neurospheres microdialysis and HPLC. Ten min baseline samples were collected for 1 h. were prepared from embryonic day 15 transgenic mouse embryos expressing Rats then received an injection of cocaine (15 mg/kg; i.p.) and samples were green fluorescent protein, and transplanted into an intact or lesioned taken for 2 h. The cocaine-induced increase in DA levels was enhanced in entorhino-hippocampal formation of young adult mice. One week after cocaine pre-exposed rats, and BUP greatly potentiated this sensitized transplantation, grafted cells closely attached to the host tissue and after two response. The cocaine pre-exposed rats also showed a sensitized locomotor and three weeks a large number of grafted cells had survived and response to the cocaine challenge, but paradoxically, BUP did not potentiate differentiated into neurons. That was confirmed by expression of neuron and even reduced this behavioral response. To explore the basis of this specific marker SMI31. After transplantation into the intact brain, short finding, we studied the effect of chronic BUP on NAc levels of GLU before processes emerged from the transplant, which did not reach the hippocampal and after an acute injection of cocaine (15 mg/kg; i.p.). Preliminary results formation. In contrast, when neurospheres were transplanted into a host brain show that basal levels of GLU were enhanced in BUP-treated rats, but in which the entorhino-hippocampal projection was mechanically lesioned cocaine had no effect. While it remains to be seen how BUP affects GLU the neurosphere-derived cells showed a directed migration towards the levels in cocaine-sensitized rats, these higher basal levels of GLU induced by dentate gyrus of the hippocampus and, in several cases, extended a strong BUP could possibly affect responses to cocaine in cocaine-sensitized rats. axonal projection towards the dentate gyrus. Some of these fibers did, Support Contributed By: Canadian Institutes of Health Research however, stop at the level of the hippocampal fissure and some of the outer molecular layer and of the dentate gyrus was observed. Just three weeks after transplantation of cortex-derived neurospheres immunostaining with anti- 170 C126 synaptophysin as a presynaptic marker revealed strong expression in the HYPERMETHYLATION OF THE GABAA RECEPTOR ?1 termination area of the newly developed Tau-GFP axons within the host SUBUNIT IS ASSOCIATED WITH ALTERED DNA hippocampal part indicating the formation of synapses in this area. Our METHYLTRANSFERASE EXPRESSION IN THE BRAINS OF results show that transplantation of immature neural cells cannot only be DEPRESSED SUICIDE VICTIMS beneficial by supporting the local neurons in the host brain and inducing M O. Poulter 1 L. Du 3, I. Weaver 4, M. Palkovits5, G. Faludi5, Z. Merali neural plasticity, but that such transplants might indeed be able to replace a 3, M. Szyf 4 and H. Anisman2,3. 1. Cell Biology Research Group, Robarts degenerated or axotomized neuronal population with the restitution of the Research Institute, UWO. London. 2. Neuroscience Research Group, original axonal projection. Carleton University Ottawa. 3. Royal Ottawa Hospital Ottawa. 4 Dept Pharmacology McGill University. 5, Semmelwiess University, Budapest Hungary 172 C128 HUMAN PROSTAGLANDIN H SYNTHASE (HPHS)-2-DEPENDENT Epigenetic mechanisms may be involved in long-term gene expression REACTIVE OXYGEN SPECIES (ROS)-MEDIATED programming responsible for stressor reactivity. To assess the possibility, that CYTOTOXICITY CAUSED BY DOPAMINE, ITS PRECURSOR AND major depressive disorder (MDD) may be similarly associated with METABOLITES epigenetic phenomena we examined the expression of DNA methyl Annmarie Ramkissoon (1)* and Peter G. Wells (1,2). (1) Faculty of transferase (DNMT) mRNA in several brain regions of MDD patients who Pharmacy and (2) Dept. of Pharmacology, University of Toronto had committed suicide. We found that DNMT gene transcripts were deregulated in several brains regions, including fronto polar cortex, PHS-2 is implicated in neurotoxicity associated with neurodegenerative amygdale and paraventricular nucleus of the hypothalamus. In addition, diseases but the mechanism is unclear. Neurotransmitters such as dopamine although transcript abundance of various forms of DNMT was highly (DA), its precursor L-dihydroxyphenylalanine (L-DOPA) and metabolite correlated in normal controls, this coordination of DNMT isoform expression dihydroxyphenylacetic acid (DOPAC) may serve as substrates for PHS- was diminished in suicide brain. Next we examined gene specific aberrations dependent bioactivation in the brain to free radical intermediates that in DNA methylation in the frontopolar cortex the GABAA receptor ?1 generate potentially neurotoxic ROS, as shown using purified ovine PHS or subunit promoter region, whose transcript is under-expressed in microsomal preparations. However, few studies have evaluated human PHSs suicide/MDD brains. Indeed, three CG sites were hypermethylated relative to in intact cells. CHO-K1 cell lines stably expressing hPHS-2 and controls. These data suggest that epigenetic mechanisms may alter gene untransfected CHO-K1 cells were used to investigate hPHS-2-dependent expression in suicide/MDD. cytotoxicity. Cells were activated with arachidonic acid (AA), and PHS-2 activity measured by production of prostaglandin E2 (PGE2) using a PGE2 enzyme immunoassay. PHS activity in AA activated cells was up to 40-fold 171 C127 higher in hPHS-2 cells compared to untransfected CHO-K1 cells; activities HOW MUCH CAN EMBRYONIC CORTEX-DERIVED were reduced without AA (p<0.01). The role of hPHS-2 in neurotransmitter- NEUROSPHERES TRANSPLANTATION LEAD TO NEURONAL mediated cytotoxicity was measured by the release of the lactate REPLACEMENT OR PARTIAL RECONSTRUCTION OF dehydrogenase enzyme (LDH). hPHS-2 cells incubated for 6 hr with DA, L- DAMAGED PERFORANT PATHWAY AND FUNCTIONAL DOPA, DOPAC and homovanillic acid (HVA) showed an increase in LDH RECOVERY? release compared to the vehicle control (p<0.001). Cytotoxicity was Vesna Radojevic* and Josef P. Kapfhammer. Anatomy Institute of Basel, increased further by AA-activation (p<0.05) while cytotoxicity was lower in Switzerland untransfected CHO-K1 cells (p<0.05). hPHS-2 cells were preincubated with 250 U/ml of polyethylene glycol-conjugated catalase (PEG-catalase), which Neural transplantation is an attractive strategy for the replacement of detoxifies ROS, and then treated with DA, L-DOPA or DOPAC at 1000 uM neurons that have been lost because of neurodegenerative processes, vascular for 6 hr with or without AA. PEG-catalase reduced the cytotoxicity of DA, insults or axonal lesions. However, the effectiveness and widespread L-DOPA and DOPAC in hPHS-2 cells both with and without AA (p<0.001). application of this approach clinically has been limited primarily because of These results suggest the cytotoxicity in hPHS-2 cells treated with DA, L- ethical concerns and poor donor supply of human fetal neural tissue. DOPA and DOPAC, and the enhanced effect of AA activation, are mediated Neurospheres have emerged as a possible donor material, particularly by ROS. Further, endogenous neurotransmitters, their precursors and because they can be expanded in vitro and have a good tendency to metabolites, can generate ROS by PHS-2-catalyzed bioactivation, so CNS differentiate into neurons. The purpose of this study was to assess the short hPHS-2 expression may contribute to cytotoxicity. This mechanism may be

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involved in neurodegenerative changes associated with aging and drugs like suppressing conditioned gaping in this model. URB597 prolongs the action amphetamines, which initiate neurotransmitter release. Since the cytosolic of the endogenous cannabinoid anandamide (AEA) by inhibiting fatty acid concentrations of precursors and metabolites are often higher than that of the amide hydrolase (FAAH), which rapidly deactivates AEA. Here, we present neurotransmitters, bioactivation of the former may contribute substantially to evidence that OND is ineffective in reducing the expression of conditioned PHS-catalyzed oxidative macromolecular damage and cytotoxicity in vivo. gaping (Experiment 1), while pre-treatment with two doses of URB597 (0.1 [Support: CIHR, CIHR/Rx&D HRF]. and 0.3 mg/kg) suppressed the expression of conditioned gaping (Experiment 2) elicited by an odour-laced context, previously paired with lithium-induced sickness, as a model of AN in rats. 173 C129 CERULOPLASMIN IS PROTECTIVE AFTER SPINAL CORD CONTUSION INJURY 175 C131 K.I. Rathore, B. Kerr, R. Lopez-Vales, SY Jeong, P. Ponka and S. David. ALTERED LYSOPHOSPHATIC ACID-STIMULATED CALCIUM Centre for Research in Neurosciencem, McGill University Health Centre, RESPONSES IN BIPOLAR DISORDER PATIENTS SUGGESTS Montreal; Lady Davis Institute, Jewish General Hospital, Montreal (2) TRANSIENT RECEPTOR POTENTIAL CHANNEL DYSFUNCTION *Roedding, Angela; Perova, Tatiana; Li, Peter; Warsh, Jerry. Cellular and Despite being essential for a number of metabolic processes, Iron (Fe2+) is Molecular Pathophysiology, Centre for Addiction and Mental Health; also a potent generator of free radicals that produce tissue damage. The Psychiatry, University of Toronto; Institute of Medical Science, University of processes and mechanisms that control its levels in the CNS are therefore Toronto; Pharmacology, University of Toronto especially important in cases involving trauma, hemorrhage and inflammation. Ceruloplasmin (Cp) is a ferroxidase that converts toxic ferrous Introduction: Chronic treatment with lithium attenuates lysophosphatidic iron to its non-toxic ferric form. We have previously reported that a GPI- acid (LPA, 100 μM) stimulated calcium (Ca2+) responses in B- linked form of this enzyme is the major form of Cp in the CNS and is lymphoblast cell lines (BLCLs), but the mechanism(s) involved and whether expressed by astrocytes. GPI-Cp is also necessary for iron efflux from there is an impairment of this response in bipolar disorder (BD) patients is astrocytes in vitro. Here we have assessed the role of Cp in preventing iron- uncertain. LPA shares a structurally similar fatty acid side chain with the cell mediated secondary damage after spinal cord contusion injury (SCI). We permeable diacylglycerol analogue, 1-oleoyl-2-acetyl-sn-glycerol (OAG), report that iron accumulates at the lesion site after injury and that there is which is a known agonist of subtypes 3, 6 and 7 of the canonical transient greater accumulation in mice deficient in Cp. The physiological importance receptor potential (TRPC) cation channel subfamily. Accordingly, the of Cp is underlined by the fact that locomotor functional recovery is objective of this study was to characterize the involvement of this TRPC significantly impaired in Cp-/- mice. Fewer motor neurons survive in the channel subfamily in the LPA-stimulated Ca2+ response of BLCLs and the spinal cords of Cp-/- mice and there is evidence of greater demyelination at extent to which this response is altered in cell lines from BD patients as the lesion site. In addition, a number of other biological markers of oxidative compared with controls. Methods: TRPC subtypes expressed in BLCLs were and nitrosative damage markers are increased in the injured spinal cords of determined by immunoblotting and RT-PCR. To distinguish the TRPC-like Cp -/- mice. Finally, the treatment of wildtype injured animals with an iron character of Ca2+ responses in BLCLs, divalent cation (barium versus Ca2+) chelator SIH, promoted functional recovery, indicating that iron contributes selectivity of thapsigargin (TG)-, LPA-, and OAG-activated responses was to continued SCI pathology. The results we will present indicate that there is assessed. Gadolinium sensitivity was used to determine the store-operated a co-ordinated iron-homeostatic response to SCI in wildtype mice, which is nature of the responses. The phospholipase C (PLC) dependence of agonist dysregulated in mice deficient in Cp. There is a cell specific upregulation of responses was assessed by a PLC inhibitor, U73122. The magnitude and rate proteins involved in the trafficking (DMT1 and FPN1) and the storage of iron of LPA-induced Ca2+ mobilization was measured in BLCLs from 42 patients (ferritin) after SCI, suggesting that astrocytes and macrophages at the lesion with a DSM-IV diagnosis of BD-I and in 25 healthy control subjects. Results: site play distinct roles in this response. Taken together our data provides Only TRPC1, 3 and 5 are expressed in BLCLs. Significant barium influx, of evidence for an iron-homeostatic response to SCI, in which ceruloplasmin a magnitude similar to OAG-mediated responses, occurred upon addition of plays an integral role. Ceruloplasmin is crucial in curtailing iron-associated LPA, but not TG. TG-provoked Ca2+ influx was completely inhibited by 15 damage after SCI. Importantly, treatment with an iron chelator is effective in μM gadolinium, whereas LPA-stimulated responses were minimally promoting functional recovery in wildtype mice, suggesting that the iron- affected. Gadolinium (≤100 μM) pre-treatment potentiated the homeostatic response is amenable to pharmacological intervention. OAG-activated Ca2+ response. Cell lines from BD-I patients showed an enhanced (40%) rate of rise of intracellular Ca2+ levels ([Ca2+]i) (F1,63=5.2, p=0.03) but not magnitude of the response (F1,63=1.0, p=0.3) to 174 C130 100 μM LPA compared with controls. EFFECTS OF ONDANSETRON AND URB597 ON THE Conclusions: The results suggest that LPA stimulates Ca2+ entry through EXPRESSION OF LITHIUM-INDUCED ANTICIPATORY NAUSEA channels with characteristics similar to the TRPC3 subfamily in BLCLs. IN RATS Thus, the findings of an enhanced LPA-stimulated rate of rise in [Ca2+]i *Erin M. Rock (1), Cheryl L. Limebeer (2), Klaus-Peter Ossenkopp(2), from BD compared with healthy subjects may implicate dysfunction of Daniele Piomelli (3), and Linda A. Parker (1). (1) Department of TRPC3-like Ca2+ entry in the pathophysiology of BD. Psychology, University of Guelph, Guelph, (2) Department of Psychology, University of Western Ontario, London, (3) Department of Pharmacology, University of California at Irvine, Irvine CA, USA 176 C132 NTS1-PREFERRING AGONISTS PRODUCE SPINAL Cancer patients undergoing chemotherapy treatments often report ANTINOCICEPTION IN A FORMALIN TONIC PAIN MODEL anticipatory nausea (AN) when they are re-exposed to contextual cues G. Roussy1*, M.A. Dansereau1, K. Belleville1, N. Beaudet1, E. Richelson2 previously paired with treatment. AN is resistant to treatment with classical and P. Sarret1. 1Dept. of Physiology and Biophysics, Faculty of Medicine, anti-emetic drugs such as ondansetron (OND). Although rats do not possess Univ. of Sherbrooke, Sherbrooke, PQ, Canada. 2Dept. of Psychiatry and the mechanism to vomit, they do display conditioned gaping reactions Psychology, Mayo Clinic College of Medicine, Jacksonville, FL, USA elicited by an odour-laced context, previously paired with lithium-induced sickness—serving as a rodent model of AN. The principle consitituents in Neurotensin (NT) is neuropeptide that mediates, through three receptor marijuana, psychoactive ∆9 –Tetrahydrocannabinol (∆9- subtypes (NTS1-3), a variety of central and peripheral functions including THC) and non-psychoactive cannabidiol (CBD), are both effective in opioid-independent antinociception. Recent studies, using knock-down

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strategies, show that NTS1 is involved in acute pain. However, little is 178 C134 known about the role of NTS1 in a model of persistent pain. The aim of the NEUROTOXICOLOGICAL CHARACTERIZATION OF MDMA- present study was to determine whether intrathecal administration of NT or ANALOGS IN VITRO: IMPLICATIONS FOR THE SYMPTOMATIC NTS1 agonists, PD149163 and NT69L, induced antinociceptive responses in TREATMENT OF PD the formalin test, a model of tonic pain. All compounds were administrated D. Salomonczyk1, M. McILdowie2, J.M. Brotchie3, M. Piggott2, & J.E. intrathecally 5 minutes before the injection of 2% formaldehyde into the Nash1. 1Centre for Neurobiology of Stress, Dep. Life Sciences, University plantar surface of the right hindpaw. Intrathecal administration of NT (0.1-15 of Toronto at Scarborough, Toronto; 2School of Biomedical and Chemical g/kg) causes a dose-dependent inhibition of nociceptive Sciences, the University of Western Australia, Perth, Australia; 3AIR, behaviours in phase I (0-9 min) and phase II (21-60 min) of the formalin test. Toronto Western Research Institute, Toronto Both NTS1-agonists, PD149163 (10-120 g/kg) and NT69L (0.1- 100 g/kg), dose-dependently attenuated the formaline-induced The recreational drug ecstasy, 3,4-methylenedioxymethamphetamine behaviours. PD149163 and NT69L decrease tonic pain up to 60% and 48% (MDMA), has been shown to prolong the actions of L-DOPA while respectively and their effects were more important than that of NT. Also, the suppressing L-DOPA induced dyskinesias in both rodent and primate models co-treatment of PD149163 or NT69L and the NTS1 antagonist SR48692 of Parkinson’s disease (PD). Despite the obvious implications of these markedly reversed both PD149163- and NT69L-induced antinociception findings, i.e. that MDMA may be of therapeutic value to PD patients, demonstrating the implication of NTS1 in tonic pain. A C-Fos MDMA is toxic to serotonergic and dopaminergic neurons in rodents and cell immunohistochemistry study on spinal cord of the tested rats confirm our culture systems. Furthermore, anecdotal evidence suggests that chronic use behavioural results by demonstrating a reduction of neuronal activity of MDMA may induce parkinsonism by increasing expression of alpha- corresponding to the antinociceptive response induced by the NTS1 agonists. synuclein and neuronal inclusions. A compound possessing the therapeutic Depending of the spinal laminae observed, the neuronal activity decreased up effects of MDMA without associated neurotoxic and psychotropic properties to 44% and 48% for NT69L and PD149163 respectively. These results would be an attractive candidate for development in the symptomatic demonstrate that NTS1 receptors are involved in the mediation of the treatment of PD. We therefore examined the neurotoxicity of several MDMA analgesic effects of NT in persistent pain and suggest that NTS1-selective analogs bearing different substituents at the alpha-position. The effects of agonists may represent a new line of analgesic compounds. (Supported by MDMA analogs ATK-0001, ATK-0090, ATK-0091, ATK-0101, ATK-0102, CIHR, FRSQ, and NIMH) and ATK-0104 on cell viability were determined using AlamarBlue fluorescence assays. The catecholaminergic neuroblastoma cell line, SH- SY5Y, was exposed to full dose response curves (1µM-600µM) of each 177 C133 analog for 24 hours. MDMA significantly reduced cell viability by 73±6.6% IN DEPTH ANALYSIS OF GRAFT IMPLANTS IN A at 600µM (P<0.01, ANOVA, Dunnett’s comparisons post-hoc. (n=6)). HUNTINGTON’S DISEASE PATIENT: LEAD INTO LONG-TERM Analogs ATK-0001 (600µM), ATK-0090 (30µM), and ATK-0102 (600µM) GRAFT SURVIVAL, DEVELOPMENT AND CONNECTIVITY significantly reduced cell viability as well, though not to the extent of that of 1,2Cicchetti F., 4,6,7Saporta S., 1Saint-Pierre M., 3Gould P., 4,5,6Freeman MDMA (43±3.4%, 12±2.6%, and 36±2.0%, respectively, P<0.01, ANOVA, T. 1Centre de Recherche en Neurosciences, CHUL, RC-9800, 2705, Dunnett’s comparisons post-hoc. (n=6)). Analogs ATK-0091 and ATK-0101 Boulevard Laurier, Québec; 2Département de Médecine, Université Laval, minimally reduced viability (11±2.4% and 15±0.9%, respectively) at 600µM Québec; 3Service d’anatomopathologie et cytologie, Hôpital de l’Enfant- (P<0.01, ANOVA, Dunnett’s comparisons post-hoc. (n=6)). Analog ATK- Jésus, Québec; 4Department of Neurosurgery, 5Department of 0104 did not decrease cell viability at any concentrations examined, and Pharmacology and Experimental Therapeutics; 6The Neuroscience indeed induced insignificant increases in cell proliferation. Given that Program, University of South Florida, Tampa, FL; 7Departments of MDMA analogs ATK-0091, ATK-0101 and ATK-0104 appear not to be Anatomy, Women’s Center, Tampa FL, USA neurotoxic in these studies, these compounds may warrant further investigation as symptomatic treatments for PD. Ten years ago, the first clinical trial using bilateral transplantation of fetal neural tissue in Huntington’s disease (HD) patients was conducted at University of South Florida. In this series, one patient died 18 months after 179 C135 transplantation of causes unrelated to the surgical procedures. The post- COMPLEX PHARMACOLOGICAL EFFECTS OF BIBN 4096BS IN mortem analysis was reported in 2000 and showed that six out of ten grafts SUPRASPINAL CGRPRELATED BEHAVIOURS IN MICE survived and were not affected by the disease process. Recently, a second *Ara Schorscher-Petcu1,2, Jeffrey S. Mogil3 & Rémi Quirion1,2,4,. patient of the initial trial died, nine years post-surgery. This unique case 1McGill University, Dept of Neurology & Neurosurgery, 2Douglas Hospital provides the opportunity to answer important questions related to 1) the Research Center, 3McGill University, Dept of Psychology, 4McGill survival and neuronal organization of implants 9 years post-surgery, 2) graft University, Dept of Psychiatry health from an immunological and pathological perspective and 3) the integrative and functional connectivity of the graft within the host. Thus far, Calcitonin gene-related peptide (CGRP) is a 37-amino acid neuropeptide we have performed a 3D computerized reconstruction on 80% of the grafted widely expressed throughout the central nervous system and enriched in tissue, the remaining 20% is currently being processed for electron dorsal root ganglion nociceptive neurons where it contributes to pain microscopy (EM) and DiI tracing to investigate graft-host connectivity. Five transmission. Although little is known about the effects of supraspinal CGRP, graft sites have been identified in each hemisphere; which contain striatal animal behavioural data and human clinical biochemistry point towards a markers such as calbindin, a marker of striatal projection neurons and contribution of CGRP to depression- and anxiety-related behaviours. This calretinin, found in a sub-population of striatal interneurons. Results also hypothesis is supported by the strong interaction between the CGRP and indicate that the graft is almost entirely devoid of an astrocytic and dopaminergic systems. To explore the contribution of CGRP to centrally macrophagial response, as assessed by the markers GFAP and HLA-DR, and mediated behaviours, we performed intracerebroventricular (i.c.v.) injections is not affected by the pathology as demonstrated by the absence of EM48 of CGRP and a non-peptidergic CGRP receptor antagonist, BIBN 4096BS, in (abnormal human huntingtin protein) and ubiquitin (nuclear inclusions) C57BL/6 mice. Mice were tested for thermal pain thresholds using the paw- staining. Evaluation of this HD case will help provide knowledge regarding withdrawal test (PWT), or screened for anxiety- and depression-like long-term graft survival and functionality. This new information is critical, behaviour using the elevated plus maze (EPM) and the forced swimming test particularly if such therapies will be utilized in young patients with an (FST), respectively. In the PWT, CGRP increased latencies whereas BIBN expectation of lifetime benefit. 4096BS decreased latencies. In the EPM, BIBN 4096BS significantly

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increased the number of open arm entries (OAE) and the time spent in open and hands with mutilation of fingers, toes, as well as Charcot's joint disease. arms (OAT). CGRP showed a non-significant tendency to increase OAE, but HSAN type II is an autosomal recessive disorder with the onset of not OAT. However, in the FST, both CGRP and BIBN 4096BS significantly symptoms in infancy or early childhood. This would suggest congenital onset decreased non-swimming time. mostly involving the distal portions of upper and lower limbs and absence or These results suggest that BIBN 409BS acts as a CGRP antagonist in diminution of tendon reflexes. Recently, linkage analysis mapped the HSAN supraspinal pathways involved in pain sensation, whereas it likely acts as a II locus to chromosome 12p13.33, where three different protein truncating CGRP receptor agonist within brain circuits involved in anxiety- and mutations were identified in a predicted novel open reading frame embedded depression-like behaviour. In this context, both molecules display an within intron 8 of the PRKWNK1 gene. By screening the HSN2 gene in one anxiolytic and antidepressant-like action in mice. This work has been of our patients, we identified a heterozygous nonsense mutation in HSN2 supported by grants from CIHR and NIH, and a DAAD scholarship to A.S.P. ORF. This mutation was carried by the patient and his asymptomatic brother, and inherited from the father. No additional mutation was detected in the ORF of the predicted gene. We therefore screened the entire coding sequence 180 C136 of WNK1 and found a second nonsense mutation located in exon 6 of the INTERACTIVE EFFECTS OF PERINATAL AND POST-WEANING gene. The mutation identified in the patient was inherited from the mother DIETS ON AMPHETAMINE-INDUCED LOCOMOTION IN THE and was absent in the unaffected brother. RT-PCR and RACE experiments ADULT OFFSPRING using adult mouse nervous system RNA showed fusion of HSN2 ORF with A. Taylor, A. Cantor, T. Quinn, S. Tobin, B. Woodside, U. Shalev*. Center exons 8 and 9 of PRKWNK1 gene. Western blots, using an antibody against for Studies in Behavioral Neurobiology, Concordia University, Montreal HSN2 ORF, detected a ~ 200 KD protein in the adult mouse nervous tissues. Using Northern blot analysis with a specific probe for HSN2 ORF, a ~ 9-10 In rats, maternal diet during the perinatal period and lactation can change kb band was also detected in RNA preparations from the adult mouse both metabolism and mesolimbic dopaminergic function in the adult nervous tissues. We have carried out experiments using offspring. However, the nature of the change in dopaminergic function is not immunohistochemistry and in situ hybridization and have concluded that the clear. One study reports that a high-fat maternal diet during late gestation WNK1/HSN2 protein is highly enriched in the peripheral nervous system and lactation results in increased sensitization to amphetamine-induced and is expressed by satellite glia cells in DRGs, neurons, and Schwann cells hyper-locomotion, while a second study reports reduced amphetamine- in the adult mouse peripheral nervous system. induced locomotion. Moreover, there are indications for an interaction between the effects of maternal diet and post-weaning pup diet on dopaminergic function. Here we tested the effects of perinatal exposure to a 182 C138 highly palatable, high energy (HE) diet on sensitivity to amphetamine- HIPPOCAMPAL SITE(S) OF ORIGIN FOR HYPOGLYCEMIC induced hyper-locomotion, in offspring that were subsequently exposed to SEIZURES control (C) or HE post-weaning diet. Dams were fed C or HE diet Sheppy, Evan, Wu, Chiping, Zhang, Liang, Carlen, Peter. Department of throughout gestation and lactation. Male pups from both groups were Physiology, University of Toronto, Fundamental Neurobiology, Toronto weaned at postnatal day (PND) 23, and maintained on HE or C diet until Western Research Institute PND 60-65. Rats were then tested for psychostimulant-induced hyper- locomotion using low (0.5 mg/kg) and high (1 mg/kg) doses of amphetamine. Severe hypoglycemia (HG) is a detrimental consequence of diabetic Post-weaning exposure to HE diet resulted in an increased body weight and therapy. A common result of HG episodes is the development of seizures, percent body fat on PND 80. In concordance with previous observations, occurring most frequently in children with type I diabetes mellitus. At adult offspring of HE mothers weighed less than offspring of C-diet dams. present, the underlying mechanism and site(s) of origin for HG-induced There were no differences between the diet treatment groups in spontaneous seizures have not been elucidated. In this study, we examine HG-seizures in or saline-challenge-induced locomotor activity. In addition, all groups both the in vivo and in vitro setting. Firstly, we have established a novel in showed the expected dose-dependent increase in locomotion following vivo juvenile murine model that exhibits insulin-induced HG seizures with a exposure to amphetamine. However, pups from HE mothers that were consistency of over 80%. EEG recordings have demonstrated seizure-like maintained on HE diet displayed a significantly greater increase in activity occurring in both the hippocampus and cortex concurrently with locomotion following exposure to the low dose of amphetamine, compared behavioral manifestations of HG-seizures. Furthermore, we used dual to the other diet groups. No differences in hyper-locomotion were observed extracellular field recordings to observe the hippocampal site of origin for between the diet groups following exposure to the high dose of amphetamine. HG-induced seizure-like activity. Our in vitro preparation consisted of In conclusion, we found that maternal diet has long-lasting effects on the 500um and 800um-thick horizontal murine hippocampal slices, where we bodyweight of the offspring. Furthermore, our findings imply that maternal decreased ACSF glucose from 5mM to 0.5mM. We observed that interictal diet interacts with post-weaning maintenance diet to induce persistent and ictal discharges induced by HG first appear in either the CA3 or CA1 adaptations in mesolimbic dopaminergic system function in the offspring. region, followed by the dentate gyrus. Pharmacological manipulation using Such adaptations may indicate a higher risk for pathologies such as obesity AMPA/kainate, NMDA, and adenosine antagonists was also studied. Our in and drug abuse, in the adult offspring. Support contributed by: CFI, CRC (to vivo and in vitro results help elucidate an origin for HG seizures, which will US), CIHR (to BW) allow focused investigation upon the cellular mechanisms responsible for HG seizure generation.

181 C137 HSN2 OPEN READING FRAME ENCODES A NOVEL EXON FOR 183 C139 WITH NO LYSINE PROTEIN KINASE 1 (WNK1) INTRAVENTRICULAR INFUSIONS OF PROPIONIC ACID Shekarabi M*, Girard N, Riviere J-B, Hince P, Laganiere J, Dion P, Rouleau REVERSIBLY IMPAIR SOCIAL BEHAVIOR AND INDUCE AG. Center for the Study of Brain Diseases, CHUM Research Center - Notre NEUROINFLAMMATORY CHANGES IN LONG EVANS RATS Dame Hospital, University of Montreal Shultz, S., MacFabe, D.F, Scratch, S., Jackson, J., Whelan, J., Martin, S., Boon, F., Taylor, R., Ossenkopp, K.P., Cain, D.P.. The Kilee Patchell-Evans Hereditary sensory and autonomic neuropathies (HSANs) are a group of Autism Research Group, Departments of Psychology/Psychiatry, University clinically heterogeneous diseases. They are characterized by loss of pain, of Western Ontario, London pressure and thermal sensation often associated with ulceration of the feet

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BClinical observations suggest that certain dietary factors may protein coupled receptors. Little research has been done to investigate the transiently worsen symptoms in autism spectrum disorders (ASDs). relationship between antipsychotic treatment outcomes and genetic Propionic Acid (PPA) is a short chain fatty acid, an enteric bacterial by- variability in second messengers coupled to serotonin and dopamine product, and a common food preservative. We have recently found PPA can receptors. The purpose of this investigation was to examine associations elicit neurobehavioral, electrophysiological and neuropathological changes between the second messenger G-protein beta3 subunit gene (GNB3) C825T in rodents consistent with human ASDs. PPA may thus be a possible target polymorphism and antipsychotics induced weight gain treatment. . The compound linking diet, gastrointestinal physiology and behavior. The present C825T polymorphism located at exon 10 of this gene has been shown to be study examined the effects of repeated intraventricular infusions of PPA associated with alternative splicing of exon 9 (variant with higher activity). using a variety of behavioral tasks. Adult Long Evans Hooded rat pairs were We conducted a pharmacogenetic association study to examine GNB3 infused with 4µl of either PPA or PBS vehicle into the lateral ventricle. Rat genotypes in relation to weight gain after 14 weeks of antipsychotic pairs were then immediately placed in an open-field arena for 1 hr during the treatment. Subjects included fifty-nine individuals meeting DSM-IV criteria light phase and for 1 hr during the dark phase in counterbalanced order. for schizophrenia treated with different antipsychotics subsequently Observations of social behaviour were quantified using Ethovision software. genotyped for the C825T in GNB3 gene. No statistically significant Following social testing, animals were tested on the balance beam task and associations existed between our outcome variable (percentage weight in the water maze to evaluate other behavioral deficits. Following behavioral change) and GNB3 genotypes (p=0.175). These preliminary results showed analyses, animals were sacrificed and brains were examined no statistical relationship between the C825T polymorphism and weight immunohistochemically using a variety of neuroinflammatory markers. gain. Numerical differences in weight change measures between the TT vs. PPA-injected rat pairs reported impairments in social behaviour when CT/CC genotype groups indicate that G-protein second messenger systems compared to control pairs. These effects were transient and attenuated within variability coupled to primary targets of atypical antipsychotics may not approximately 30 min post-infusion. Furthermore, PPA rats were impaired in relate to side-effect in persons with schizophrenia and that future studies in the water maze and balance beam tasks in a manner reminiscent of human this area are warranted. ASDs. Neuropathological analysis of rat hippocampus and white matter showed reactive astrogliosis (GFAP) and activated microglial (CD68) response with increased blood brain barrier permeability (IgG). In 186 C142 conclusion, PPA infusions induce reversible behavioral impairments and SKIN-DERIVED PRECURSORS DIFFERENTIATED INTO neuroinflammatory changes consistent with human ASDs. SCHWANN CELLS PROMOTE REPAIR AND FUNCTIONAL RECOVERY FOLLOWING TRANSPLANTATION INTO THE INJURED RAT SPINAL CORD 184 C140 JS Sparling *(1), J Biernaskie (2), J Plemel (1), J Liu (1), F Miller (2,3), W DSCR1 FACILITATES NEURONAL APOPTOSIS Tetzlaff (1,4).. 1 University of British Columbia, ICORD; Surgery. 2 Xiulian Sun, Bin Chen, Zhuohua Zhang, Weihui Zhou, Weihong Song. Hospital for Sick Children, Develpmental and Stem Cell Biology. 3 Hospital Department of Psychiatry, Brain Research Center, The University of British for Sick Children, Physiology; University of Toronto, Molecular and Medical Columbia Genetics. 4 University of British Columbia, Zoology

Individuals with Down syndrome (DS) will inevitably develop Contusive spinal cord injury (SCI) typically results in a large cavitation Alzheimer’s Disease (AD) neuropathology after their middle age, to which with a narrow rim of spared tissue at the injury site. The loss of tissue, genes triplicated in DS may be attributable. The characteristic AD coupled with demyelination of spared axons around the lesion, disrupts neuropathology includes neuritic plaques, neurofibrillary tangles and ascending sensory and descending motor tracts, leading to a loss of function neuronal loss in the brains. The mechanism underlying neurodegeneration in below the level the injury. Natural repair mechanisms generally fail in this AD and DS remains elusive. Down Syndrome Critical Region 1 (DSCR1) setting, so the functional impairment is often permanent and severely gene locates on Chromosome 21 and has been implicated in the pathogenesis debilitating. Transplantation of exogenous cells is one potential therapeutic of DS. Our data show that DSCR1 expression is elevated in the cortex of DS strategy for the treatment of SCI, but no cell transplant has yet demonstrated and AD patients. DSCR1 expression can be activated by dexamethasone and the ability to fully repair the injured spinal cord. We have previously calcium stress respectively. Overexpression of DSCR1 in primary neurons described a multipotent skin-derived precursor (SKPs), exhibiting gene activates induces apoptosis. The neurotoxicity of DSCR1 is abolished by expression and differentiation properties characteristic of neural crest stem inhibition of DSCR1. Our data suggest that DSCR1 elevation in brain cells. In vitro, SKPs generate neural and mesodermal cell types and we have contributes to neuronal death and AD pathogenesis in DS. recently demonstrated that SKPs predifferentiated into Schwann cells (SKP- SCs) generate compact myelin in vivo. Here we investigated whether mouse naïve SKPs or SKP-SCs were capable of remyelination and repair of the 185 C141 contused adult rat spinal cord. In comparison to media injection and ANALYSIS IN G-PROTEIN BETA3 SUBUNIT GENE (C825T) subventricular zone neurosphere transplants, the naïve SKP and SKP-SC POLYMORPHISM AS A CANDIDATE GENE TO transplants exhibited greater survival, increased myelination and axonal ANTIPSYCHOTIC-RELATED WEIGHT GAIN sparing/regeneration, as well as enhanced invasion by endogenous SCs. RP Souza1,2,3, V De Luca1, MA Romano-Silva2,3, A Wong1, J Volavka4,5, Naïve SKPs showed some mesodermal differentiation and limited integration JA Lieberman6, JL Kennedy1. 1 Neurogenetics Section, CAMH and Dept. of with host tissue, making them poorly suited for therapeutic transplantation. Psychiatry, University of Toronto. 2 Grupo de Pesquisa em Neuropsiquiatria In contrast, the SKP-SCs appear ideally suited to this role, as they bridged the Clínica e Molecular, UFMG, Brazil. 3 Departamento de Farmacologia, ICB, lesion site in a rostro-caudal orientation and integrated well with host tissue UFMG, Brazil. 4 Nathan S. Kline Institute for Psychiatric Research, USA; 5 to promote axonal sparing/regeneration of a functionally appropriate New York University School of Medicine, Department of Psychiatry, USA; 6 orientation. They also showed the most efficient myelination of host axons University of North Carolina at Chapel Hill, Department of Psychiatry, USA and the most extensive recruitment of endogenous SCs in the spared rim. In agreement with the histological evidence, rats receiving SKP-SCs showed Despite advances in schizophrenia treatment, nearly 30% of patients do improved hindlimb locomotor function in open field testing relative to all not respond to atypical antipsychotic agents, such as olanzapine, clozapine other treatment groups and no indication of lowered sensory thresholds. As and risperidone. Atypical antipsychotics have high affinity for many G- these cells are harvested from skin, they are of little ethical concern, and are

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ideal for autologous transplantation paradigms that circumvent the need for channels mediate ischemic cell death in-vivo. TRPM7 expression was harmful long-term immunosuppression post-transplantation. In conclusion, suppressed in vivo using adeno-associated virus (AAV) vector –mediated SKP-SCs emerge as an excellent candidate for (potentially autologous) gene transfer of shRNA to effect RNA interference in mature neurons. The transplantation repair strategies following SCI. AAV vectors were stereotactically microinjected into adult rat brains. Efficacy of gene silencing was tested in-vitro and in-vivo by immunohistochemistry (IHC) and by RT-PCR of transfected cells isolated by 187 C143 laser dissection microcapture. Cerebral ischemia was induced using the four EXPERIENTIAL DETAILS, AND NOT TEMPORAL SPECIFICITY, vessel occlusion (4VO) model in adult Wistar rats transfected 7 days DETERMINES AUTOBIOGRAPHICAL MEMORY IN PATIENTS previously with the viral vectors. Suppression of TRPM7 channel expression WITH UNILATERAL TEMPORAL LOBE EPILEPSY OR was confirmed at the mRNA level in-vivo with the laser dissection EXCISIONS microcapture followed by PCR, and at the protein level both in-vitro and in- *Marie St-Laurent, MA 1 2, Morris Moscovitch, PhD 1 3, Brian Levine, PhD vivo using IHC. After global ischemia by 4VO, CA1 neurons in which 3 & Mary Pat McAndrews, PhD 2.. 1 Department of Psychology, University TRPM7 was suppressed exhibited significantly greater survival (395±40 vs of Toronto, 2 Toronto Western Research Institute, University Health Network, 25±4 EGFP positive CA1 neurons) and less TUNEL staining (601 vs 2154 Toronto, 3 Rotman Research Institute and Department of Psychology, TUNEL positive CA1 cells) than controls, respectively (n=6/groups). The Baycrest Centre for Geriatric Care Toronto suppression of the TRPM7 channels was confirmed both in-vitro and in-vivo using PCR and IHC techniques. TRPM7 channels play an important role The ability to retrieve autobiographical memories (AM) is dependent on mediating neuronal cell death in global ischemia. These results may have the functional integrity of the hippocampus (HC). Patients with unilateral broader significance to ischemic injury of other tissues due to the widespread temporal lobe epilepsy, involving dysfunction or lesions to the HC, are expression of TRPM7 channels. (This study was funded by CIHR, NIH, CSN impaired at recalling autobiographical episodes (Addis, 2005; Viskontas et and Krembil Seed fund - MT, and H-SS: HSFC - FOS Fellowship.) al., 2002; Voltzenlogel et al., 2006). While this impairment is clear for unique AMs, it is not clear that hippocampal damage results in an equal deficit in generic (repeated) AM recall. One study from our group using fMRI showed 189 C145 that the hippocampus is equally engaged during retrieval of both unique and EXCITOTOXIC NEUROPROTECTION IN AN IN VITRO MODEL generic personal episodes (Addis et al., 2004) and the objective of the current OF THE ISCHEMIC CONTINUUM study was to assess the impact of hippocampal damage on these two types of JS Tauskela*, M Hewitt and E Brunette. National Research Council, Institute AM. Patients with unilateral mesial temporal epilepsy (including both pre- for Biological Science, Synaptic Pathophysiology Group, Ottawa surgical and post-surgical patients) were compared to healthy controls on a modified version of the Autobiographical Interview (AI) (Levine et al., Drug(s) required to protect rat cortical neurons from increasingly longer 2002). AM narratives produced during the AI are broken down into details durations of oxygen-glucose deprivation (an OGD ‘continuum’) were that are either bound or unbound to an episode; details are further classified identified, using antagonists of NMDA (MK-801 or a glycine-site sensitive into categories that reflect different aspects of the memory. Our version of the L689,560) or AMPA (CNQX, NBQX or SYM2206) receptors, voltage-gated AI was adapted by constructing a parallel set of questions for generic Ca2+ channels (nifedipine, Ni2+ or an extracellular pH of 6.5) or compounds personal events. Results indicate that both patients with right and left TL reported to prevent TRPM7 receptor-mediated neurotoxicity in mouse dysfunction reported fewer details pertaining to the recollected event, for cortical neuron cultures (Gd3+, an nNOS inhibitor, 7-nitroindazole, or the both specific and generic personal events. The source of this deficit was the antioxidants, trolox or a metalloporphyrin, MnTBAP [Aarts et al, 2003]), at paucity of perceptual information about the personal events. These results maximally effective concentrations. Protection by a cocktail of MK-801 (2 suggest that the hippocampus plays a key role in the reconstruction of μM)/CNQX (10 μM)/nifedipine (2 μM) against 1.5 h experience-near sensory-perceptual events. The similarity of the impairment OGD was overcome if OGD was 2 h long. Increasing MK-801 to between the episodic and the generic memory conditions also suggests that ≥12 μM protected neurons against 2, but not 2.5 h, OGD. the hippocampus is not sensitive to the temporal specificity of the Replacing MK-801 with L689,560 (200 μM) protected against 2.5 h reconstructed personal events, which confirms our previous functional OGD, with protection largely reversed by glycine, but not against 3 h OGD. neuroimaging findings with healthy controls. References: Addis (2005). Increasing CNQX to ≥ 100 μM in the L689,560/nifedipine Unpublished PhD thesis, University of Toronto, Toronto, Canada.; Addis et cocktail protected against 3 h, but not 3.5 h, OGD. Replacing CNQX with al., (2004). NeuroImage, 23, 1460-71.; Levine et al. (2002). Psychology and NBQX (100 μM) and SYM2206 (30 μM) was protective at 3.5 Aging, 17, 677-689.; Viskontas et al. (2002). The Journal of Neuroscience, h, but not 4 h, OGD. The MK- 01/CNQX/nifedipine cocktails used at 1.5- 20, 5853-5857. Voltzenlogel et al. (2006). Epilepsia, 47, 1329-1336 2.5 h OGD were augmented with different drugs: (i) To determine if NMDA receptors were blocked, NMDA (0.5-2 mM) was included. NMDA was not injurious but protective, perhaps due to AMPA receptor blockade. (ii) 188 C144 Augmentation with MnTBAP (200 μM), but not with Gd3+ (5-100 MEDIATION OF DELAYED HIPPOCAMPAL NEURONAL DEATH μM), 7-nitroindazole (150 μM) or Trolox (1 mM), was FOLLOWING GLOBAL CEREBRAL ISCHEMIA BY TRPM7 protective; however, inactive ZnTBAP (50 μM) or CoTBAP (25 CHANNELS. μM), but not a potent antioxidant analog, MnTE-PyP(2) (200 *Hong-Shuo Sun1,2, Karen Jansen3, Lucy Teves1, Hong Cui1, Michael μM), were protective. Hence, TRPM7 receptors may be involved only Jones1,2, Joan Forder1, Todd E. Golde3, John F. MacDonald2, Michael in mouse cortical cultures (Aarts et al, 2003). (iii) Augmentation with low Tymianski1,2,4.. 1. Fundamental Neurobiology, Toronto Western Hospital extracellular pH (6.5) buffer or with Ni2+ (1 mM) was protective, perhaps Research Institutes, Toronto; 2. Department of Physiology, University of due to NMDA receptor blockade. (iv) In intracellular Ca2+ (Ca2+i) Toronto, Toronto; 3. Department of Neuroscience, Mayo Clinic, measurements, only protective drugs suppressed Ca2+i elevations. Results Jacksonville, Florida, USA; 4. Department of Surgery, University of Toronto suggest inadequate glutamate receptor block by MK-801/CNQX combinations, since replacement or augmentation with compounds known to Stroke is a leading cause of morbidity and mortality in industrialized block these receptors improved protection, although non-specific blockade of countries. We have recently described that TRPM7, a member of the other receptors by the high concentrations of receptor antagonists used Transient Receptor Potential channel superfamily, is important in mediating cannot be ruled out. Combination therapy with potent glutamate receptor and anoxia/reoxygenation damage in-vitro. To determine whether TRPM7 VGCC antagonists at high concentrations are required for Ca2+i-dependent neuroprotection under stringent OGD conditions.

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190 C146 analyses of brain revealed an innate neuroinflammatory response (GFAP, DELAYED CALCIUM DEREGULATION DURING NMDA CD68, IbA1) similar to that found in human ASD brain. Furthermore, PPA EXCITOTOXICITY MEDIATED BY PANNEXIN CHANNELS treated rat brain showed increased monocarboxylate transporter I Roger J. Thompson* and Brian A. MacVicar. Brain Research Centre, immunoreactivity, and increased BBB permeability (IgG, rat whole serum). The University of British Colubia, Vancouver PPA treated animals also showed increases in PhosphoCREB and vimentin immunoreactivity, both indices of a neuroplastic response. PPA effects were Over activation of glutamate receptors leads to neuronal death and is a not grossly neurotoxic as indexed by direct pyramidal cell counts and component of several neurodegenerative disorders including stroke, apoptotic markers (cleaved Caspase 3). Chronic PPA in rats increases Alzheimer’s disease and epilepsy. A key component of this cell death is locomotor activity, and induces neuroinflammatory, fatty acid transport, thought to be a delayed calcium deregulation, manifested as the sustained BBB, and neuroplastic changes, and may offer a putative animal model of influx of calcium that persists even after washout of glutamate receptor ASD’s. Sponsor: GoodLife Children’s Charities ligands. We recently reported that ischemia (oxygen / glucose deprivation) opens very large conductance cation channels, likely pannexin 1 (panx1) hemichannels and that this may be a key component of the ionic 192 C148 dysregulation observed during neuronal death (Thompson et al, 2006, THE ROLE OF DOPAMINE D1 RECEPTORS IN FOOD Science 312:924). Here we tested the hypothesis that the delayed calcium DEPRIVATION-INDUCED REINSTATEMENT OF DRUG-SEEKING deregulation upon activation of NMDA receptors is mediated by the opening Tobin, S.*, Quinn, T. & Shalev, U. Center for Studies in Behavioral of panx1 channels. We report that a cation current is activated in acutely Neurobiology, Concordia University, Montreal isolated hippocampal neurons by either intermittent (10 s applications at 1 min intervals) or continuous (5-10 min) exposure to 100 µM NMDA. The Clinical research has demonstrated that among recovering drug addicts, current was inhibited by carbenoxolone, a known blocker of gap junctions exposure to stressful events can pose a significant a risk for relapse. and pannexin or connexin channels (hemichannels). Confirmation of the role Traditionally, stress-induced relapse has been studied using an animal model of hemichannels was achieved by measuring dye flux across the plasma of footshock-induced reinstatement. More recently, however, it has been membrane of acutely isolated neurons and those in brain slices. In acutely shown that acute food deprivation (FD) stress can reinstate previously isolated neurons, NMDA evoked an intracellular calcium increase as extinguished drug-reinforced behavior. It has been suggested that stress- measured by Fluo-4 that persisted after NMDA removal. This delayed induced reinstatement of reward seeking is mediated by an increase in the calcium deregulation preceded efflux of an inert dye, calcein red-orange, incentive salience of cues previously associated with reward. This increase in from the neuron. Both the delayed calcium deregulation and calcein efflux incentive salience may be dopamine (DA) dependent. The role of DA in were inhibited by carbenoxolone. Influx of sulforhodamine 101 (SR101) footshock-induced reinstatement is unclear. For example, only the mixed DA into neurons in the CA1 region of hippocampal slices was activated by bath antagonist flupenthixol decanoate, and not the D1 receptor antagonist SCH application of NMDA and this was blocked by carbenoxolone. We conclude 23390 or the D2 receptor antagonist raclopride, has been shown to attenuate that the delayed calcium deregulation evoked by NMDA receptor activation footshock-induced reinstatement. Additionally, the involvement of DA in at excitotoxic concentrations of NMDA is mediated by hemichannel opening. FD-induced reinstatement has not been investigated. Recently, leptin, a hormone involved in the long-term regulation of feeding, has been found to suppress FD-induced reinstatement while having no affect on footshock- 191 C147 induced reinstatement. This suggests that the neuronal mechanisms INFUSIONS OF PROPIONIC ACID INDUCES INCREASED mediating footshock- and FD-induced reinstatement may be different. Here LOCOMOTOR ACTIVITY, NEUROINFLAMMATORY EFFECTS, we investigated this possibility by studying the role of the D1 receptor in FD- FATTY ACID TRANSPORT, BLOOD BRAIN BARRIER AND induced reinstatement. Rats were trained to lever press for heroin over a NEUROPLASTIC CHANGES IN RATS FOLLOWING period of 10 days (.05 mg/kg/infusion, i.v.; Days 1-5: three 3-h sessions, INTRAVENTRICULAR INFUSION-RELEVANCE TO AUTISM Days 6-10: one 3-h session). Drug seeking behavior was then extinguished SPECTRUM DISORDERS for a minimum of 4 days. Subsequently, rats were tested twice, in a * MacFabe, D.F. Hoffman, J.E., Taylor,R.,Mohammad Asef, Y., Cain, D. P., counterbalanced order, for reinstatement: following 48 h FD, and under food- Boon, F., Kavaliers, M., Ossenkopp, K.P., . The Kilee Patchell-Evans Autism sated conditions. Prior to each test, rats were injected with one of 3 doses of Research Group, Departments of Psychology/Psychiatry, The Schulich the D1 receptor antagonist SCH 23390 (0 μg, 5 μg or 10 School of Medicine & Dentistry, The University of Western Ontario, London μg/kg, s.c.). It was found that SCH 23390 dose-dependently attenuated drug-seeking behavior when animals were food deprived, yet had no effect Innate neuroinflammatory changes, alterations in fatty acid metabolism on responding when animals were not food deprived. This finding supports a and blood brain barrier (BBB) permeability may be involved in the role for DA in FD-induced reinstatement of drug seeking behavior. pathophysiology of autism spectrum disorders (ASDs). Furthermore pre or Support contributed by: CFI, CRC (to US) perinatal infectious processes, as well as dietary or digestive system factors have been suggested in ASD cause or symptom exacerbation. Propionic acid (PPA) is a short chain fatty acid, a by-product of many enteric bacteria, and 193 C149 a food preservative. PPA is actively transported by monocarboxylate MORPHINE AND ULTRA-LOW DOSE NALTREXONE: transporters in the gut and CNS, and has widespread effects on cellular DIFFERENTIAL EFFECTS ON MORPHINE-INDUCED metabolism and immune function. We found PPA that can elicit behavioural CATALEPSY, FEEDING AND ANALGESIA and neuropathological changes in rodents and may be a model for ASDs. To Katharine J. Tuerke*1, Richard J. Beninger1,2, and Mary C. Olmstead1. evaluate the behavioural and neuropathological effects of chronic Depts. 1Psychology and 2Psychiatry, Queen's University, Kingston intraventricular PPA infusions in rodents, adult Long-Evans rats received twice daily intraventricular infusions (4µl/animal) of pH 7.5 buffered PPA, Classic pharmacological theories predict that opioid receptor antagonists or .1M PBS vehicle for 14 consecutive treatment days. Immediately block the behavioural effects of opioids. Surprisingly, co-administration of following ventricular infusion, animals were individually placed into an ultra-low dose (ULD) of the opioid receptor antagonist naltrexone with automated open field and locomotor activity assessed for 30min (Versamax). morphine enhanced morphine’s analgesic effects. This paradoxical effect was Following behavioural analyses, animals were sacrificed and brains attributed to the activation of mu opioid receptors that mediate morphine- examined immunohistochemically. PPA treated animals showed increases in induced catalepsy, feeding, drinking and analgesia. We hypothesized that locomotor activity and repetitive stereotypies. Immunohistochemical ULD naltrexone will enhance morphine-induced catalepsy and feeding. In

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experiment 1, rats (N = 56) were randomly assigned to saline, morphine (10 There is a lot of controversy on the prognostic value of admission blood mg/kg), co-treatments of morphine (10 mg/kg) plus naltrexone (molar ratios pressures in acute ischaemic stroke. There has been no study on the effect of of 1,000,000:1; 500,000:1; 100,000:1) or naltrexone alone groups. For 7 admission blood pressures on stroke outcome in Nigeria. The objective of consecutive days, catalepsy and analgesia were assessed 30 and 60 min post this study was to study the effect of blood pressures measured on admission injection using the bar and tail-flick tests, respectively. ULD naltrexone co- on 30-day mortality and neurological handicap in Nigerians. administered with morphine did not significantly affect morphine-induced This study was conducted at the Lagos University Teaching Hospital, Lagos, catalepsy but significantly and dose-dependently attenuated tolerance to Nigeria. Patients who met the inclusion criteria were prospectively recruited morphine’s analgesic effect. In experiment 2, rats (N = 35) were randomly from the emergency medical unit of the hospital. Information which included assigned to saline, morphine (4 mg/kg) or co-treatments of morphine (4 age, sex, level of consciousness and stroke severity using the National mg/kg) plus naltrexone groups (molar ratios of 1,000,000:1; 500,000:1; Institute of Health Stroke Scale (NIHSS) was obtained in a standardized 100,000:1) and tested for food and water intake. Rats then underwent a 7- manner. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) day sensitization period with a morphine dose of 10 mg/kg and naltrexone in were measured while pulse pressure (PP) and mean arterial pressure (MAP) the same ULD ratios. On days 1, 7 and 21, food and water intake were again were derived. Patients were managed conservatively and periodically assessed using 4 mg/kg of morphine and naltrexone in the ULD ratios. Food evaluated for progress and/or development of complications. Primary and water intake were augmented by morphine but were not further enhanced outcome was mortality within 30 days while secondary outcome was level of by co-administration of ULD naltrexone plus morphine. All together these handicap on the modified Rankin Scale. 100 patients with a mean age of experiments showed that ULD naltrexone co-administered with morphine 58.56±14.12 years were studied; 53 of them were males. Overall mortality specifically enhanced morphine’s analgesic effects but not its cataleptic, rate was 28%. There was no significant correlation between admission blood hyperdipsic or hyperphagic effects. These data also showed that morphine’s pressures and 30-day mortality (SBP: r = -0.05, p= 0.62; DBP: r = -0.12, p= paradoxical analgesic effects are not the result of changes in morphine- 0.23; PP: r = 0.01, p= 0.90; MAP: r = -0.09, p= 0.36) or modified Rankin induced catalepsy. Results suggest that the actions of ultra-low doses of Score (SBP: r = -0.11, p= 0.29; DBP: r = -0.13, p= 0.21; PP: r= -0.06, p= naltrexone co-administered with morphine are specific to antinociceptive 0.54; MAP: r = -0.13, p= 0.21). In conclusion, admission blood pressures do systems and do not generalize to other behavioural systems affected by not have significant influence on 30-day mortality and level of handicap in morphine. (Funded by NSERC) Nigerian Africans with acute ischaemic stroke.

194 C150 196 C152 BDNF AND PROBDNF IN CORTICAL SYNAPTONEUROSOMES IDENTIFICATION OF A CRITICAL DEVELOPMENTAL WINDOW FOLLOWING KAINIC ACID-INDUCED SEIZURES IN RATS FOR THE EFFECTS OF MORPHINE ADMINISTRATION ON THE *Gautam R Ullal(1), Ronald J Racine (1),and Margaret Fahnestock(2).. SURVIVAL OF ADULT-GENERATED GRANULE CELLS IN THE Dept. of (1) Psychology, Neuroscience and Behaviour and (2) Psychiatry and DENTATE GYRUS Behavioural Neurosciences, McMaster University, Hamilton Afra H. Wang1-2 , Cátia Teixeira11-4, Paul W. Frankland1-3,. 1. Institute of Medical Science, University of Toronto. 2. Program in Neurosciences and Brain-derived neurotrophic factor (BDNF) plays a crucial role in Mental Health, The Hospital for Sick Children, Toronto. 3. Department of activation-induced neuroplasticity. Seizures are known to increase BDNF Physiology, University of Toronto, 4. Graduate Program in Areas of Basic mRNA and protein expression. Furthermore, seizures also enhance cleavage and Applied Biology (GABBA) Universidade do Porto, Portugal of the precursor form of BDNF, proBDNF, to BDNF by increasing the expression of various intracellular and extracellular proteases. There is Morphine administration reduces both proliferation and survival of adult- increasing evidence that BDNF mRNA and protein are present at the synapse generated granule cells in the dentate gyrus of the hippocampus (Eisch et al, and that processing occurs close to the synapse. In this study, we asked 2006; Nestler et al, 2000). To evaluate whether there is a critical period for whether seizures change the subcellular distribution and processing of the effects of morphine on survival, mice were injected daily with morphine BDNF. We used Western blotting to measure relative levels of BDNF and (0, 10, 20 mg/kg) for 5 days either 1 week or 3 weeks after treatment with the proBDNF in isolated synaptoneurosomes from cerebral cortex of rats cell proliferation marker 5-bromo-2’-deoxyuridine (BrdU). All mice were subjected to kainic acid-induced status epilepticus seizures. The post- sacrificed 4 weeks after BrdU treatment. Using immunohistochemical synaptic density protein PSD95 was used as a marker for synaptoneurosomal methods, we quantified BrdU+ cells throughout the anterior-posterior extent enrichment. All samples were normalized to β-actin as a stable of dentate gyrus. Numbers of BrdU+ cells were decreased in mice treated reference gene. In naïve rat cortex, higher levels of BDNF were detected in with highest dose of morphine 1 week, but not 3 weeks, after BrdU treatment. synaptoneurosomes compared to cell body fractions. Seventy-two hours Our data provide evidence that morphine administration reduces survival of following kainic acid-induced seizures, there was a significant increase in adult-generated granule cells in the dentate gyrus, and identify a critical BDNF protein in both synaptoneurosomes and cell bodies. Surprisingly, developmental window for these effects. In the future, we will evaluate there was no difference in levels of proBDNF between the whether similar critical windows exist for the effects of other drugs of abuse synaptoneurosomes and cell bodies of naïve rats, and seizures did not on survival of adult-generated neurons in the hippocampus. increase proBDNF levels in either compartment. Thus, BDNF, but not proBDNF, is preferentially localized to synaptic regions in naïve cortex. The increase in BDNF levels following status epilepticus seizures, without 197 C153 changes in proBDNF, may be due to localised synthesis of BDNF and ISOLATION AND CHARACTERIZATION OF A NOVEL regional conversion of proBDNF to BDNF, coupled with activity-induced MORPHINE-DEPENDENCE CANDIDATE HUMAN GENE increased expression of protease enzymes that convert proBDNF to BDNF. ENCODING ZINC FINGER AND RNA-BINDING MOTIF 1- CONTAINING PROTEIN ZCRB1 Mary X. Gao1, Haoran Wang2,3,4*. 1Cancer Research Program, Hospital 195 C151 for Sick Children, 2Department of Psychology and 3Center of Biological DOES ADMISSION BLOOD PRESSURE REALLY PREDICT POOR Timing and Cognition (CBTC), University of Toronto, Toronto, Canada; OUTCOME IN ACUTE ISCHAEMIC STROKE? - A STUDY OF 100 4Neuroscience Research Institute, Peking University, China NIGERIAN AFRICANS Wahab KW*. Department of Medicine, Irrua Specialist Teaching Hospital, Addiction to opiates such as morphine is a major public health concern. Irrua, Edo State, Nigeria. A more thorough understanding of the molecular mechanisms of opiate

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addiction can lead to better treatment options in the future. Until recently, 199 D402 little was known about the changes in gene expression that underlie these MINOCYCLINE PROTECTS THE BLOOD-BRAIN BARRIER AND effects. Here we isolated a novel morphine dependence candidate human REDUCES EDEMA FOLLOWING INTRACEREBRAL gene ZCRB1 with differential display. ZCRB1 expression is up-regulated by HEMORRHAGE IN THE RAT acute (3 hours), but not chronic morphine treatment (morphine Jason K. Wasserman and Lyanne C. Schlichter. Toronto Western Research hydrochloride, 1-10 mg/ml). The acute cellular level morphine dependence is Institute, University Health Network, Dept. of Physiology, Univerisity of consistent with the dynamic change of intracellular CREB concentration. Toronto ZCRB1, a novel zinc finger CCHC-type and RNA binding motif 1 containing protein, encodes a nuclear protein (217 residues). The ZCRB1 gene consists Intracerebral hemorrhage (ICH) results from rupture of a blood vessel in of 8 exons and 7 introns. It is mapped to 12q12, which is within a locus the brain. After ICH, the blood-brain barrier (BBB) surrounding the reported for Parkinson's disease. The 5’-flanking region contains an enhancer hematoma is disrupted, leading to cerebral edema. In both animals and core motif and binding sites for AP-1, 2 and LF-A1. ZCRB1 is characterized humans, edema coincides with inflammation, which is characterized by by an RNA-binding motif and a CCHC Zinc finger motif. The latter overlaps production of pro-inflammatory cytokines, activation of resident brain the C..C…GH….C core nucleocapsid motif. ZCRB1 is conserved through microglia and migration of peripheral immune cells into the brain. zebrafish to human, and shares homology with cold-inducible RNA-binding Accordingly, inflammation is an attractive target for reducing edema protein. Transfection assay showed ZCRB1 is located in the nucleoplasm, but following ICH. In the present study, BBB damage was assessed by outside the nucleolus. ZCRB1 gene expression was inhibited by 30-36°C and quantifying intact microvessels surrounding the hematoma and by measuring upregulated by 39°C incubation in SH-SY5Y neural cells. ZCRB1 gene brain water content 3 days after ICH induced by collagenase injection into expression is highest in the heart and testes, lower in the cerebellum and the rat striatum. In the injured brain, the water content increased in both lowest in the liver in mice. ZCRB1 mRNA expression is specifically elevated ipsilateral and contralateral hemispheres compared with the normal brain. in hepatocarcinoma HepG2 cells. In this study, we have cloned and Immunostaining showed a loss of intact microvessels surrounding the characterized a novel morphine-dependence candidate human gene encoding hematoma, as judged by collagen type IV staining, and co-localization of a multifunctional zinc-finger protein that is involved in morphine MMP-12 with damaged microvessels. MMP-12 was also observed for the dependence, heat shock and hepatocarcinoma. (*Thanks Drs. L Li, B Wang, first time in neurons. Quantitative real-time RT-PCR revealed an up- N Hori, K Sato, J Yeomans, and the staff of NRI for technical assistance regulation of inflammatory genes associated with BBB damage; IL-1beta, and/or valuable discussion. This research is supported by grants to XG, HW TNF-alpha, matrix metalloproteases MMP-3, MMP-9, and most notably, and JY. HW is currently at the University of Toronto) MMP-12. Dual-antibody labelling demonstrated that neutrophils were the predominant source of TNF-alpha protein. Intraperitoneal injection of the tetracycline derivative, minocycline, beginning 6 hours after ICH reduced 198 D401 microvessel loss and edema, decreased TNF-alpha and MMP-12 expression, CALCITONIN GENE-RELATED PEPTIDE IS INVOLVED IN and reduced the numbers of TNF-alpha positive cells and neutrophils in the CHRONIC MORPHINE INDUCED ACTIVATION OF P38 brain. Thus, minocycline, administered at a clinically relevant time, appears MITOGEN-ACTIVATED PROTEIN KINASE to target the inflammatory processes involved in edema development after Zhiyong Wang, Weiya Ma and Remi Quirion. Douglas Hospital Research ICH. Center, and Department of Psychiatry, McGill University, Montreal

Opiates including morphine are potent analgesics to treat moderate and 200 D403 severe pain. The usefulness of opiates is compromised by the rapid REGULATION OF BACE1 EXPRESSION BY INTERACTION OF development of tolerance to their antinociceptive effects. We have previously HIF1 AND SP1 shown that chronic morphine administration up-regulates the pain-related Shengcai Wei, Xiulian Sun, and Weihong Song. Department of Psychiatry, peptide, calcitonin gene-related peptide (CGRP), in primary sensory neurons Brain Research Center, The University of British Columbia and CGRP receptor antagonists are able to reverse the development of morphine tolerance, suggesting the role of CGRP in the development of The pathogenesis of sporadic Alzheimer’s disease (AD) is largely morphine tolerance. In this study, we explored the mechanisms how CGRP unknown. Patients with stroke or cerebral infarction showed poorer cognitive contributes to the development of morphine tolerance. Repeated intrathecal performance and greater severity of clinical dementia. Vascular risk factors (i.t.) injection of morphine (15μg) for 7 days evoked a gradual have been suggested to be associated with development of AD. A reduced tolerance to morphine induced anti-nociception, which was reversed by co- cerebral perfusion is a common vascular component among AD risk factors. administration of the non-peptide CGRP receptor antagonist BIBN4096BS Hypoxia is a direct consequence of hypoperfusion. The hypoxia signal (0.1μg). Interestingly, i.t. repeated morphine injection also increased transduction pathway plays a major role in vascular development and the phosphorylation (p) of p38 mitogen-activated protein kinase (MAPK) in ischemia, as well as neurodegeneration. Hypoxia inducible transcription glia-like cell profiles in the dorsal horn of lumbar spinal cord. These pp38 factor (HIF1) is a central mediator of hypoxia signal transduction pathway positive cell profiles were identified as microglia since they co-expressed through which cells in the brain respond to reduced oxygen tension. microglia marker OX-42. BIBN4096BS was also able to attenuate chronic Previously we have reported that BACE gene promoter contains HIF1 and morphine increased pp38 in microglia. In contrast, i.t. repeated morphine Sp1 element. Hypoxia and Sp1 overexpression increased APP CTF injection did not alter the phosphorylation of Akt and GSK3 in the production by increasing BACE1 expression and transcription in cells. dorsal horn of lumbar spinal cord. Taken together, our data suggest that the BACE1 expression was significantly upregulated in mice under hypoxia activation of p38 MAPK in microglia is an important signalling event treatment. Knockout of Sp1 or Knockdown of HIF1 significantly inhibited underlying the development of morphine tolerance. Morphine up-regulated BACE1 gene transcription. Interaction of Sp1 and HIF1 is critical for the CGRP likely plays a role in the activation of p38 MAPK signalling. BACE1 gene expression. (Supported by the Canadian Institutes of Health Research)

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201 D404 203 D406 GAMMA OSCILLATIONS, TREMOR AND PARKINSON’S INCREASE IN SPONTANEOUS, ACTION POTENTIAL DISEASE DEPENDENT GLUTAMATE RELEASE DURING EARLY Weinberger M1, Hutchison WD1,2, Lozano A2, Hodaie M2, Dostrovsky ISCHEMIA CAN BE PREVENTED BY CALCIUM CHELATOR JO1,2. 1 Dept. of Physiology, Univ. of Toronto, 2 Toronto Western Hospital, BAPTA-AM Toronto Hui Ye1,2,*, Shirin Jalini3, Liang Zhang1,2 and Peter L Carlen1,2. Toronto Western Research Institute1, University Health Network, Department of Resting tremor, one of the main symptoms in Parkinson’s disease (PD), Physiology2, Institute of Medical Science3, University of Toronto is not a consistent feature of the disease. Unlike rigidity and akinesia there is no correlation between the severity of PD tremor and the degree of dopamine Spontaneous synaptic release of glutamate during early ischemia is deficiency in the striatum or the progression of the disease. Moreover, PD neurotoxic and may cause perturbation to normal neural network functions. patients with predominant resting tremor have better prognosis and slower These releases are mediated by both action potential (AP) dependent and AP- disease progression than patients with primarily akinesia and rigidity. Recent independent mechanisms. Previous studies have shown that AP-independent studies in humans suggest that the akinesia in PD is related to abnormal (miniature) release was enhanced during ischemia, by Ca2+ release from the increased beta (15-30 Hz) synchronous oscillatory activity in the basal internal stores. However, neuronal mechanism underlying the AP-dependent ganglia and decreased gamma (35-80 Hz) activity. In this study, we recorded spontaneous release remains unclear. In this paper, we show that the AP- local field potential (LFP) activity from the subthalamic nucleus (STN) in 7 dependent release is also increased in the CA1 pyramidal neurons in the PD patients who exhibited intermittent periods of resting tremor during the hippocampus during 2 min hypoxia/hypoglycemia (H/H) episode. time of functional neurosurgery. In 6 out of the 7 patients, LFP oscillatory Enhancement in the activity of the presynaptic CA3 neurons is sufficient and activity in the low gamma frequency range (35-55 Hz) was found to be necessary to cause this increase. BAPTA-AM, an intracellular calcium increased during periods of tremor and this activity was maximal in the buffer, blocks the increase during H/H, by attenuating CA3 activity, and by dorsal part of STN. Furthermore, LFP gamma power was positively compromising the ability for the action potentials in triggering spontaneous correlated with tremor amplitude when averaged across subjects. These release from the CA3 terminals. Both lesion of the pre-post synaptic results suggest that increased gamma activity in STN may be related to the pathway, and buffering of the intracellular calcium, could provide significant mechanism of generation of resting tremor in PD patients. Since gamma LFP rescue strategies to the excessive glutamate release and perturbed network activity in STN is thought to reflect its role in movement, the increased functions during early ischemia. gamma activity observed during PD tremor may be due to a compensatory mechanism generated in order to overcome the akinesia and which may lead to tremor as a side effect. Supported by CIHR FRN 42505. 204 D407 MEMORY DEFICITS IN ALZHEIMER’S DISEASE: A POSSIBLE ROLE OF CREB? 202D405 Adelaide Yiu1,2 & Dr. Sheena Josselyn1,2,3. 1Program in Neurosciences and ANALYSIS OF THE BINDING ABILITY OF MOUSE BRAIN Mental Health, Hospital for Sick Children, Toronto. 2Institute of Medical ALPHA-SYNUCLEIN TO PRESYNAPTIC MEMBRANES. Sciences, 3Dept. of Physiology, University of Toronto Sabine Wislet-Gendebien*, Loren Oschipok, Diana Marsillo, Cheryl D’Souza, Paul Fraser, and Anurag Tandon. Centre For Research in Alzheimer’s disease (AD) is a progressive neurodegenerative condition Neurodegenerative Diseases, University of Toronto that is initially characterized by mild memory impairments that progress to more global cognitive deficits, behavioural impairment and eventually death. Alpha-Synuclein is a 140 amino acid protein, associated with presynaptic As memory deficits are the core feature of AD, novel treatments may benefit membranes in the brain and constituting one of the major components of from building on basic research studying the molecular basis of normal Lewy bodies (a hallmark of Parkinson's disease). Three missense mutations memory formation. Amyloid plaques and neurofibrillary tangles in the (A30P, A53T and E46K) in the gene encoding alpha-synuclein are associated hippocampus, amygdala and cerebral cortex serve as a criterion for with rare autosomal dominant forms of familial Parkinson's disease. postmortem diagnosis of the disease. As amyloid plaques consist mainly of a However, the normal conformation of alpha-synuclein in vivo, its subcellular 40-42 amino acid peptide termed beta-amyloid peptide (A), localization in neurons, and the corresponding effects of the clinical overproduction and accumulation of A has been proposed to be a mutations are poorly understood. In the present study, we analysed the cause of AD. The mechanism underlying the mild memory deficits observed capacity of cytosolic alpha-synuclein to interact with biological membranes. before the onset of clear brain pathology are unknown. Exogenous In contrast to E.coli-expressed recombinant alpha-synuclein, the cytosolic application of A in vitro disrupts neuronal signaling and alpha-synuclein from mouse brain has significantly lower membrane binding compromises the function of CREB (cAMP responsive element binding ability. To assess whether alpha-synuclein binding properties might be protein), a transcription factor critical for normal memory formation. regulated, we first analysed the effect of cytosolic factors (proteins and Therefore, disrupted CREB function may account for early memory deficits lipids), ATP and calcium on E.coli-expressed alpha-synuclein. Both ATP and in AD. Here we examined if increasing CREB function improves memory in cytosol increased the binding of E.coli-expressed alpha-synuclein. Although mouse that modesl AD. TgCRND8 transgenic mice overexpress a human ATP also increased the binding of mouse brain cytosolic alpha-synuclein, the gene associated with familial AD (APP) and recapitulate key aspects of AD, overall binding efficiency of the murine expressed alpha-synuclein remained including increased levels of A and memory deficits. We, and poor compared to the E.coli-expressed alpha-synclein. Furthermore, a others, have shown that the TgCRND8 mice show robust spatial memory primary difference between E.coli-expressed alpha-synuclein incubated with deficits, as assessed by the Morris water maze. To examine whether cytosol versus cytosolic mouse brain alpha-synuclein is that the murine- increasing CREB function rescues this memory deficit, we used viral expressed alpha-synuclein co-elutes with high molecular weight markers on mediated gene transfer techniques to increase CREB levels and function in glycerol gradients suggesting the possibility that alpha-synuclein in the hippocampus of transgenic and wild-type littermate control mice. Our mammalian brain participates in high molecular weight complexes. The preliminary results show that increasing CREB rescues some of the spatial identification of the proteins involved in those complexes would allow a memory deficits in this mouse model of AD. These results may serve as a better understanding of the alpha-synuclein function. step towards developing novel treatment strategies to reverse or delay the early memory deficits of AD.

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205 D408 conditions, AIF levels were found to decrease in the mitochondrial POSTERIOR HYPOTHALAMIC STIMULATION AMELIORATES compartment while increased in the cytosolic and nuclear compartments. HALOPERIDOL INDUCED BRADYKINESIA IN AN ACTIVE Pretreatment of neurons 10 microM nicotine for 1 hour with decreased the AVOIDANCE TASK occurrence of beta-amyloid -induced cell death and attenuated the increase in Calvin K. Young*1, Jesse Jackson1, Bin Hu2 and Brian H. Bland1. AIF levels in the cytosol and nucleus. Conclusion: These results suggest that 1Department of Psychology; 2Department of Clinical Neurosciences, the neuroprotection conferred by nicotine against beta-amyloid -induced University of Calgary, Calgary toxicity involves a reduction in caspase-independent programmed cell death through the inhibition of AIF nuclear translocation. Supported by CIHR Parkinson’s disease (PD) is principally a movement disorder characterized by muscle rigidity, tremors and bradykinesia/akinesia. One of the most effective treatments of PD is deep brain stimulation (DBS). DBS in 207 D410 the subthalamic nucleus is particularly effective in ameliorating bradykinesia PROMOTION OF SPINAL CORD REPAIR AND REGENERATION (slow movement) and drug-induced dyskineisa (involuntary movements). IN CERVICAL SPONDYLOTIC MYELOPATHY BY TARGETING Thalamic DBS is particularly effective in tremor stoppage. DBS effect on THE FAS PATHWAY akinesia (poverty of movement), however, remains less established. In rats, Wen Ru Yu and Michael G. Fehlings. Division of Neurosurgery, University the stimulation of the posterior hypothalamic area (PH) elicits spontaneous, of Toronto, Division of Cellular and Molecular Biology, Toronto Western natural behaviours. The vigour and intensity of ongoing behaviour are Research Institute and Spinal Program, Krembil Neuroscience Center. positively related to the stimulation intensity. In this study, we investigated University of Toronto the effectiveness of PH stimulation on haloperidol-induced movement deficits. Haloperidol is an antipsychotic with anti-dopaminergic Cervical spondylotic myelopathy (CSM) is a chronic degenerative (predominantly at the D2 receptor) actions. It produces the rigidity, tremor disorder of the spinal cord characterized by cord compression due to and bradykinesia/akinesia seen in PD patients, hence has been used spondylosis, degenerative disc disease or ossification of the posterior extensively to probe the movement-related deficits in PD...... Thirteen Long- longitudinal ligament. The autosomal recessive mutant Tip-toe Walking Evans rats were implanted bipolar stimulating electrodes in the PH. Upon Yoshimura (twy/twy) mouse has a spontaneous mutation in the nucleotide recovery, pretests determined stimulus intensities to elicit natural pyrophosphatase (Npps) gene, and as a result spontaneously develops spontaneous behaviour. The animals were subsequently trained in an active calcified deposits at C1-C2 vertebral levels causing cervical spinal cord avoidance task to reach target criterion (10 consecutive successful escapes compression and resulting in spinal cord pathology and neurological deficits, under 10 seconds). Saline, haloperidol or no injections were administered on which mimics human CSM. Approaches to enhance neurological recovery separate days when animals became proficient at the task. Animals received and reduce neural cell death in CSM would be of major clinical importance. saline had similar escape latencies and success rate compared to animals that Previous work from our laboratory indicated that the Fas receptor is involved received no injections. Conversely, animals that received haloperidol were in the pathobiology of cell death in human CSM and twy/twy mice. We not able to escape foot shocks. Posterior hypothalamic stimulation had little hypothesized that neutralization of Fas ligand (FasL) by a function-blocking- effect on escape latency and no effect on escape success in animals injected antibody will reduce cell death, the extent of inflammation and promote with saline or received no injections. However, PH stimulation was effective axonal growth resulting in functional neurological recovery in twy/twy to reverse haloperidol-induced bradykinesia and rescued the animals’ task mouse model of CSM. We tested neutralization of Fas-mediated apoptosis in performance back to criterion. The data illustrates the effectiveness of PH the twy/twy model in vivo. We treated 4 month-old twy/twy mice with FasL stimulation to produce context-relevant behaviours and offer a novel locus specific antibody (MFL3; BD Bioscience) 50ug i.p twice weekly for up to 4 for possible DBS in PD treatment. weeks (n=12 per group). Control mice were treated with IgG and artificial CSF alone. Functional neurological recovery was assessed by quantitative footprint gait analysis at weekly intervals for the 4 weeks treatment and 206 D409 measuring weight of body for twice (from the beginning and end of NICOTINE PROTECTS AGAINST BETA-AMYLOID treatment). The injury sites were examined using quantitative NEUROTOXICITY AND ATTENUATES NUCLEAR histomorphometric and western blotting approaches to examine growth- TRANSLOCATION OF APOPTOSIS-INDUCING FACTOR (AIF) IN associated protein-43 (GAP-43), NF200, NeuN, GFAP, MaC-1, FasL and CULTURED RAT CORTICAL NEURONS Caspase-9 for role of axonal function, glial scar, inflammation and cell death. Wenfeng Yu1, Naguib Mechawar1, Slavica Krantic2, Rémi Quirion1. Twy/twy mice treated with FasL by function-blocking-antibody were capable 1Douglas Hospital Research Center, Department of Psychiatry, McGill of reduction of weight loss and improvement of neurological functional University, Montréal; 2INMED, INSERM U29, Luminy, Marseille, France recovery, mirrored by an increase in regenerating fibers and upregulation of GAP43, a decrease in the infiltration of macrophages and reactive microglia Introduction and objective: Accumulation of beta-amyloid is thought to and the inhibition in GFAP positive glial scar as well as a reduction in play a central role in the progressive loss of synapses and neurons occurring caspase 9 activation after chronic SCI. in Alzheimer's disease. Recent evidence indicates that beta-amyloid-induced In the present study, Our results are consistent with previous work from neurotoxicity is likely associated with both caspase-dependent and - our and others that deficiency of Fas (Yoshino et al. 2004; Casha et al. 2005) independent programmed cell death. The latter type is mediated by the and neutralization of Fas ligand (FasL) (Demjen et al. 2004) resulted in nuclear translocation of the mitochondrial flavoprotein, apoptosis-inducing reducing oligodendroglial cell death and improving behavioral and factor (AIF). Given the well-established neuroprotective properties of histological outcomes after SCI. Neutralization of Fas and FasL in the nicotine against beta-amyloid -induced neurotoxicity, here we investigated twy/twy mouse model of CSM attenuates neuronal and oligodendroglial cell the effects of nicotine on beta-amyloid -induced caspase-independent cell death and promotes improved functional neurological recovery. Our data death and AIF nuclear translocation in rat cortical neurons in vitro. Methods: will lay the foundation to develop novel therapeutic approaches to target Primary cultures of rat cortical neurons were exposed to various spinal cord degeneration associated with CSM. concentrations of beta-amyloid 25-35 and beta-amyloid 1-40 with or without 10 microM nicotine. Cell viability was measured using the MTT assay, and AIF protein expression was measured by immunoblot. Results: 48 hour- exposure to either beta-amyloid 25-35 (20, 30 or 40 microM) or beta-amyloid 1-40 (20 or 40 microM) led to significant increases in cell death. Under these

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208 D411 210 D413 AN INVESTIGATION OF THE INDUCTION AND RECOVERY OF DECREASED SIRT1 CORRELATES WITH TAU PATHOLOGY IN RAT BRAIN CYP2D PROTEIN AND MRNA LEVELS BY ALZHEIMER’S DISEASE NICOTINE Carl Julien*1,2, Cyntia Tremblay1,2, Alix Phivilay1,2, and Frédéric Jiang Yue*; Sharon Miksys; Ewa Hoffmann; Rachel F. Tyndale. The Centre Calon1,2. 1Centre de Recherche en Endocrinologie Moléculaire et for Addiction and Mental Health, and the Department of Pharmacology, Oncologique, CHUL, Quebec, 2Faculté de pharmacie de l'Université Laval, University of Toronto Quebec

Human CYP2D6 is involved in the metabolism of many centrally active Sirtuins have been recently shown to increase the lifespan of several drugs, neurotoxins and endogenous neurochemicals. CYP2D6 levels are animal species possibly through regulation of cellular metabolism. Since age higher in many brain regions of smokers suggesting induction by nicotine. and metabolism-related disorders are risk factors for Alzheimer’s disease CYP2D activity among rat brain regions correlates with protein and mRNA (AD), we have hypothesized that SIRT1, a nuclear human sirtuin, plays a role levels. We investigated whether nicotine can induce brain CYP2D in rat, and in AD. To test that hypothesis, we have compared the concentration of SIRT1 the recovery time course. Rats were treated either once with saline or nicotine in the parietal cortex, the hippocampus and the cerebellum of AD patients (1 mg base /kg, s.c.), and sacrificed at 8 h after the treatment, or daily for 7 (n=19) with age-matched Controls (n=20), using Western immunoblots. We days and sacrificed 0.5-24 h after the last treatment. CYP2D protein levels have also measured SIRT1 levels in the temporal cortex of an AD mouse were detected quantitatively by immunoblotting and in specific neural cells model (3xTg-AD) of tau and beta-amyloid pathologies (n=26) compared to using immunocytochemistry. CYP2D mRNA levels were assessed by slot- control littermates (n=26). The extent of beta-amyloid pathology was blotting. There were no changes in brain CYP2D levels after a single nicotine determined by measuring soluble and detergent-insoluble Abeta injection. Brain CYP2D levels were maximally induced at 8 h in all three peptide40/42 load by Elisa. Concentrations of total and phosphorylated tau in regions assessed after nicotine-treated for 7 days, which returned to control parietal cortex homogenates were determined using Western immunoblots. levels by 12 h. At 8 h post-nicotine treatment, CYP2D levels were We found a significant decrease of the protein SIRT1 in the parietal cortex significantly (p<0.05) higher than in saline-treated controls in cerebellum (–43% ; p=0.0014), but not in the hippocampus or the cerebellum of AD (1.4-fold), hippocampus (1.3-fold) and striatum (3.2-fold), and trended to be patients compared to Controls. The decrease of SIRT1 remained at –43% higher in frontal cortex, brainstem and thalamus. Induction was brain region- when expressed as a ratio over actin (p=0.0126). Levels of SIRT1 were and cell-specific for example in some striatal neurons, and in cells in the correlated positively with brain mass (r2=+0.138 ; p=0.0199) and total cerebellar granular layer and white matter. There was no increase in brain soluble Tau (r2=+0.221 ; p=0.0025), and negatively with the duration of CYP2D mRNA levels following 7 days of nicotine treatment. Hepatic symptoms (r2=–0.549 ; p=0.0010), soluble Abeta40 (r2=–0.138 ; CYP2D levels were unchanged at all times tested. This data demonstrates p=–0.0198), insoluble Abeta42 (r2=–0.157 ; p=0.0124), insoluble that CYP2D protein in rat brain, but not liver, can be induced by 7 days of phosphorylated Tau (r2=–0.211 ; p=0.0033), and total insoluble Tau nicotine treatment and that the induction of brain CYP2D levels utilizes a (r2=–0.267 ; p=0.0009), but not with insoluble Abeta40, age, post-mortem post-transcriptional mechanism. This model will be useful for investigating delay or brain pH. In contrast, SIRT1 levels in the cortex of 16-month-old many aspects of CYP2D induction including the molecular mechanisms and 3xTg-AD mice with significant Abeta and tau pathologies were similar to behavioral consequences. The findings suggest that humans exposed to control animals. Our results indicate that the decrease of SIRT1 in AD is nicotine, including current and passive smokers and those on nicotine associated with beta-amyloid and tau pathologies in advanced stages of the replacement treatment, may have increased in situ CYP2D-mediated disease. metabolism of centrally acting drugs, neurotoxins, and endogenous neurochemicals owing to the higher CYP2D6 in the brain. 211 D414 ENVIRONMENTAL CHALLENGE DURING PREGNANCY: 209 D412 ANALYSIS OF DOPAMINERGIC-RELATED MRNAS IN A MOUSE ANTIGENIC-INDUCED EXPRESSION OF BRAIN DERIVED MODEL TO STUDY AUTISM NEUROTROPHIC FACTOR IN MULTIPLE SCLEROSIS Florence I. Roullet.*1,3,4; Lori Wollaston2, Geoffrey Hall3,4, Denys Wenjun Zhu, Mike Namaka, Kim Madec, Yuewen Gong deCatanzaro.2, and Jane A. Foster3,4. 1 : Postdoctoral Fellow, Brain-Body Institute; 2 : Undergraduate Student, Department of Psychology, McMaster Multiple sclerosis (MS) is a chronic inflammatory disease in young University, 3 : Brain Body Institute, St. Joseph’s Healthcare; 4 : Department adults of western world which results in the demyelination, axonal lost and of Psychiatry & Behavioural Neurosciences, McMaster University neurons degeneration in the central nervous system. Current treatments for MS including immunomodulation and immune deviation are only partially In the present study we hypothesized that prenatal exposure to an anti- effective due to they are no cure in remyelination, axonal and neurons epileptic drug, valproic acid (VPA) at a specific timepoint will impact the regeneration. Neuroprotection will be a promising strategy aim at prevention later neurodevelopment in the offspring. Indeed, environmental factors have of the damage pf various neuronal cells and promoting regeneration. Because been associated with neurodevelopmental illnesses like schizophrenia or brain derived neurotrophic factor (BDNF) is a potent neurotrophin with the autism. Moreover, epidemiological studies reveal that VPA exposure during profound effects on neuronal survival and repairing, in our research, we use the first trimester in humans could induce higher incidence of autism in the the myelin basic protein as the antigen to induce EAE animal model of MS offspring. In our experiments, we examine the impact of the VPA in rats and determine the expression of BDNF in the dorsal root ganglia administration in pregnant mice on pup development. Previously we (DRG), spinal cord and brain at a series of time points with the demonstrated that prenatal exposure to VPA leads to alterations in postnatal immunohistochemistry, semi-quantitative RT-PCR and fully-quantitative growth and maturation as well as deficits in social behaviour. Here we Real-time PCR in data analysis. Preliminary results from our laboratory studied the dopaminergic system at the level of gene expression using in situ indicate that there is an up regulated expression of BDNF in EAE active hybridization. Dopamine (DA) has been intensively linked to stereotypy and group comparing to naïve group. It seems plausible that BDNF maybe exact this altered behaviour has been described in the autistic population. A functional consequences in the remitting phase of RRMS and will be prenatal role of DA in the incidence of autism has been suggested. Our neuroptotective implications for the therapy of MS in the future. preliminary data show a significant sex-related difference in D2 receptor (D2R) mRNA expression in the striatum. We are also analyzing D1 and D2 receptors mRNA expression in the nucleus accumbens. Additional animal

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imaging experiments are underway to examine dopaminergic system Oxidative stress and ER stress (i.e. calcium deregulation & protein function in VPA and control mice, with [123I]altropane (Boston Life aggregation) have been implicated in acute and chronic neurodegenerative Sciences) using SPECT-CT. This experiment will provide new insight in the conditions. However, the signaling pathways that activate the apoptotic role of dopaminergic neurotransmission in brain neurodevelopment and response in these conditions are not well understood. Here, we demonstrate extend the face validity of a potential animal model to study autism. that the Bcl-2 family member PUMA is transcriptionally upregulated in response to several different oxidative and ER stressors, and that PUMA is essential for neuronal apoptosis in these contexts. Furthermore, we 212 D415 demonstrate that the cyclin-dependent kinase inhibitor (cdki), flavopiridol, DISTRIBUTION OF KCNQ3 CHANNELS IN MIDBRAIN blocks oxidative and ER stress-induced PUMA transcription and neuronal DOPAMINE CELLS OF A NEURODEVELOPMENTAL RAT cell death. Ectopic expression of either DN-Cdk4 or the Cdk4 inhibitor MODEL OF SCHIZOPHRENIA p16(INK4A) also significantly reduced PUMA induction and apoptosis in Deemyad T*, McLean JH, Adamec R, Chen X. Division of Basic Medical these paradigms. Finally, we demonstrate by chromatin immunoprecipitation Sciences, Memorial University; Department of Psychology, Memorial that the Cdk4 targets, Rb and p130, along with their respective cognate Universty, St. John's, Newfoundland binding partners, E2F1 and E2F4, endogenously associate with the PUMA promoter, in vitro. Taken together, these results suggest that in oxidative and Dysfunction in midbrain dopaminergic system has been implicated in ER stress-triggered neuronal apoptosis, the activation of cdks regulates the schizophrenia. One known mechanism for promoting DA release is burst transcriptional induction of the crucial pro-apoptotic BH3-only domain gene firing of dopamine (DA) cells. However, whether alterations in firing pattern PUMA. increases DA release in schizophrenia is unclear. It has been shown that blocking M channels induces burst firing in VTA dopamine cells. Changes in M channels can be a plausible explanation for increased excitability and burst 215 D418 firing of DA cells in schizophrenia. In neonatal ventral hippocampal lesion MONOAMINE NEUROTRANSMITTER METABOLISM IN POST- rats, a neurodevelopmental model of schizophrenia, the expression and MORTEM BRAIN OF SUBJECTS WITH AUTISM distribution of KCNQ3 subtype of M channels in midbrain, the VTA in *Kristine LP Garcia , Peter Szatmari, and Margaret Fahnestock. particular, immunohistochemically were studied. The VTA of neonatal Department of Psychiatry & Behavioural Neurosciences, McMaster ventral hippocampal lesion group revealed a decline in immunoreactivity to University, Hamilton, Ontario KCNQ3 in comparison with the sham group. In double immunoflorecence labeling with tyrosine hydroxylase and KCNQ3 co- localization of both Autism is a pervasive developmental disorder believed to be the result of antagonists in DA cells was observed. In conclusion, it is possible that developmental defects in the brain. Elevated monoamine neurotransmitters decreased expression of M channels in DA cells results in changes in serotonin, dopamine, and norepinephrine in the blood of subjects with autism excitability and firing pattern to increase DA transmission. have been reported in the literature. Also, drugs that target these neurotransmitters have been found effective in treating some of the behavioural symptoms. These findings implicate dysregulation in these 213 D416 neurotransmitter systems; however the mechanism that accounts for this is A GIGAXONIN VARIANT PREVENTS GIANT AXONAL unknown. To investigate whether dysregulation occurs centrally, the NEUROPATHY IN MICE. enzymes responsible for monoamine neurotransmitter synthesis, Florence Dequen, Pascale Bomont, Geneviève Gowing and Jean-Pierre degradation, and reuptake were examined in the post-mortem brains of Julien. 1Molecular Endocrinology and Oncology Research Center, Anatomy subjects with autism. The mRNA levels of tryptophan hydroxylase 2, and physiology department, Medecine faculty, Université Laval, Québec, serotonin transporter, dopamine beta-hydroxylase, and monoamine oxidase Canada ; 2Ludwig Institute for Cancer Research University of California, A were measured using real-time RT-PCR. Beta-actin was also measured as San Diego a reference gene. Tryptophan hydroxylase 2 is the rate-limiting enzyme for serotonin synthesis in the brain, and the serotonin transporter is responsible Gigaxonin is a ubiquitously expressed 68kDa protein known to play a for serotonin reuptake into the pre-synaptic neuron. Dopamine beta- role in cytoskeleton stability. Several mutations in Gan gene lead to giant hydroxylase is responsible for converting dopamine into norepinephrine, and axonal neuropathy, a rare autosomal recessive disorder. As in many monoamine oxidase A is responsible for the breakdown of monoamines. neurodegenerative diseases, giant axonal neuropathy is associated with These targets were measured in the fusiform gyrus and striatum, as studies abnormal accumulations of intermediate filaments. To further investigate the have shown that these areas are structurally and functionally abnormal in role of cytoskeletal components on intermediate filaments toxicity, we have subjects with autism. The mRNA levels of all targets in subjects with autism generated a new mouse model deficient for gigaxonin. The knock-out mice compared to controls were not significantly different. This was consistent are viable, reproduce normally and do not show any overt phenotype. both with and without normalization to beta-actin. There were also no Interestingly, protein analyses revealed an increase in the level of various correlations between any of the targets and age or post mortem interval. Our intermediate filaments, including the neurofilaments subunits, that correlates results show no differences in mRNA; however enzymatic activity has not with a change in axons caliber in L5 ventral roots. However, a 47.5 kDa been examined and other brain areas may be relevant. variant has been detected which suggest the presence of a Gan isoform only in the spinal cord. These results suggest that giant axonal neuropathy is provoked by the loss of both Gan isoforms in mice. 216 D419 SELECTIVE EARLY LOSS OF THE MOST FORCEFUL MOTOR UNITS IN A MOUSE MODEL OF ALS 214 D417 J. Hegedus (1), C. T. Putman (1,3), N. Tyreman (1),, T. Gordon (1,2). (1) CYCLIN-DEPENDENT KINASES TRIGGER NEURONAL Centre for Neuroscience, (2) Division of Physical Medicine and APOPTOSIS BY REGULATING THE TRANSCRIPTIONAL Rehabilitation, Faculty of Medicine and (3) Biochemistry Laboratory, INDUCTION OF PUMA Faculty of Physical Education and Recreation, University of Alberta, Ben Fuerth (1&2), Meera Karajgikar (1), Diana Steckley (1), and Sean Edmonton, AB., Canada, T6G 2S2 Cregan (1&2). 1. Robarts Research Institute; 2. Department of Physiology & Pharmacology, University of Western Ontario Anatomical studies suggest that the largest caliber motor axons are most vulnerable to die-back in both human patients and transgenic mouse models

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of Amyotrophic Lateral Sclerosis (ALS). In contrast, electromyographic uncertain mechanisms. We have previously shown that invading macrophage studies of functional motor units have failed to uncover selective loss and derived cyclooxygenase 2/prostaglandin E2 (COX2/PGE2) is involved in the disagree regarding the time-course of die-back. Here, electrophysiological pathogenesis of neuropathic pain in the acute stage. In this study, we ask and immunohistochemical methods were combined to enumerate and whether invading macrophage derived COX2/PGE2 contribute to the characterize functional motor units in a pre-symptomatic SOD1G93A mouse maintenance of neuropathic pain at a rather advance stage. Both tactile model of ALS. At 60 days of age, a full month before the reported onset of allodynia and heat hyperalgesia, but not cold allodynia, are still exhibited in symptoms, the number of motor units in SOD1G93A mouse tibialis anterior rats 18 months after partial sciatic nerve ligation (PSNL). At this stage, OX- (TA) muscle was reduced by ~60%. In agreement with anatomical data, 42 or ED1 immunoreactive (IR) invading macrophages still existed in both there was a preferential loss of the most forceful motor units, and the average proximal and distal stumps of ligated nerve, but much less abundant motor unit force declined to ~50% of controls. Despite the reduction in compared to 2 and 4 weeks postlesion. The up-regulation of COX2 and force, there was no parallel change in the number of muscle fibers innervated microsomal prostaglandin E synthase 1 (mPGES1) remained in these per motor unit (innervation ratio; IR). Dissociation of motor unit force and macrophages and endothelial cells in small blood vessels, suggesting that IR occurred because the average force produced by the innervated muscle PGE2 is over-produced in injured nerves in these rats. Moreover, pro- fibers declined due to an increase in the proportion of smaller, less forceful inflammatory cytokine interleukin-6 (IL-6) was also increased in invading type IIA and IID/X muscle fiber types. Two parallel processes, 1) preferential macrophages. PSNL increased phosphorylation of CREB, a transcription denervation of type IIB muscle fibers and 2) activity-dependent conversion factor and hall marker of the cell activation, is still evident in the ipsilateral of type IIB muscle fibers accounted for the change in fiber type proportions. dorsal horn of lumbar spinal cord. Perineural injection of a selective COX2 In conclusion, our findings show that the less forceful motor units are inhibitor NS-398 (60µg/rat) significantly relieved both tactile allodynia and preferentially spared in pre-symptomatic SOD1G93A but do not undergo heat hyperalgesia for more than 72 hours. NS-398 also reduced IL-6 compensatory functional enlargement. expression in injured nerves and increased pCREB in the dorsal horn. Intraperitoneal injection of NS-398 at the same dose produced a delayed relief on neuropathic pain. Taken together, our data indicate that partial nerve 217 D301 injury can produce a rather prolonged neuropathic pain and invading ISOLATION AND CHARACTERIZATION OF LCHN: A NOVEL macrophage derived PGE2 is involved in the maintenance of this chronic FACTOR INDUCED BY TRANSIENT GLOBAL ISCHEMIA IN THE pain condition. Local injection of selective COX2 inhibitors is a plausible ADULT HIPPOCAMPUS avenue to treat neuropathic pain and avoid serious cardiovascular side Benjamin P Jung1, Guangming Zhang1, Warren Ho1, Denis GM Jugloff1, effects. (Supported by the Canadian Institutes of Health Research) Herman H Cheung2, James W Gurd2, M Christopher Wallace1,3,5, James H Eubanks1,4,5. 1Division of Cellular and Molecular Biology, Toronto Western Research Institute, Toronto, ON, Canada; 2Centre for the 219 D303 Neurobiology of Stress, Department of Life Sciences, University of Toronto, EFFECT OF TAU DYSFUNCTION ON NERVE GROWTH FACTOR Scarborough, ON, Canada; 3Division of Applied and Interventional RETROGRADE TRANSPORT Research, Toronto Western Research Institute, Toronto, ON, Canada; * Raheleh Masoudi(1) and Margaret Fahnestock(1,2). (1)Department of 4Department of Surgery (Neurosurgery), University of Toronto, Toronto, ON, Biology and (2)Department of Psychiatry and Behavioural Neurosciences, Canada; 5Institute of Medical Science, University of Toronto, Scarborough, McMaster University, Hamilton, Ontario ON, Canada Basal forebrain cholinergic neurons (BFCNs) are dependent on nerve Using mRNA differential display to identify cerebral ischemia- growth factor (NGF) for survival and function. In aged brain and also in responsive mRNAs, we isolated and cloned a cDNA derived from a novel Alzheimer’s disease, BFCNs atrophy is associated with loss of the NGF gene, that has been designated LCHN. Antisense mRNA in situ hybridization receptor, TrkA, and abnormal distribution of NGF in those neurons and in and immunoblotting confirmed LCHN expression to be induced in the rat target tissues such as cortex and hippocampus. There is a defect in retrograde hippocampus following transient forebrain ischemia. The deduced amino transport of NGF from target tissue to BFCN cell bodies in aged animals and acid sequence of the novel LCHN cDNA contains an open reading frame of in transgenic mice mimicking some Alzheimer’s disease pathology. 455 amino acids, encoding a protein with a predicted molecular mass of Hyperphosphorylation of microtubule-associated protein tau, implicated in approximately 51 kDa. Although LCHN is highly conserved between rat, Alzheimer’s disease and in tauopathies such as Pick’s disease and mouse, and human, the deduced amino acid sequence of LCHN does not progressive supranuclear palsy (PSP), leads to defects in axonal transport. possess significant homology to other known genes. LCHN However, whether the defective retrograde transport of NGF in Alzheimer’s immunoreactivity is detected within the somatodendritic compartment of disease is due to loss of TrkA or to tau hyperphosphorylation is not clear. The neurons, is also present on dendritic growth cones, but is not detected on purpose of this study was to determine whether tau hyperphosphorylation astrocytes. The induction of LCHN in the hippocampus following ischemic causes NGF retrograde transport impairment, as evidenced by increased injury may have functional consequences, as the ectopic over-expression of NGF levels in cortex and/or hippocampus. Western blotting for proNGF (the LCHN generated neurons with longer and more branched axons and NGF precursor and the dominant form of NGF in the brain) was carried out dendrites. Taken together, these data suggest that LCHN could play a role in on post mortem human cortical tissue from subjects with tauopathies and neuritogenesis, as well as in neuronal recovery and/or restructuring in the controls. Transgenic mice overexpressing GSK-3β, the most hippocampus following transient cerebral ischemia. prominent tau kinase in brain responsible for tau hyperphosphorylation, and mice with a tau mutation corresponding to the human tauopathy FTDP-17 (P301L) were similarly tested for proNGF content in cortex and 218 D302 hippocampus. Increased proNGF was demonstrated in Pick’s disease, INVADING MACROPHAGE DERIVED PROSTAGLANDINS PLAY confirming the effect of tau dysfunction on proNGF axonal transport. A ROLE IN THE MAINTENANCE OF NERVE INJURY ELICITED However, PSP brains and both GSK-3β overexpressing and P301L NEUROPATHIC PAIN AT AN ADVANCED STAGE transgenic mice showed normal levels of cortical and/or hippocampal Weiya Ma, Remi Quirion. Douglas Hospital Research Center, McGill proNGF. Interestingly, it has been shown that accumulated tau in Alzheimer’s University, Montreal and Pick’s diseases is more highly modified compared to that in other tauopathies, including PSP. This may explain the normal distribution of Chronic neuropathic pain is a serious clinical concern. It inflicts more proNGF in PSP and also in the transgenic animals, as they may have less than 1% population and the current treatments are not satisfactory due to modified tau which does not interfere with axonal transport of proNGF.

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Increased proNGF levels in Pick’s disease cortex shows that, similar to ubiquitinated inclusions that are present in Frontal Temporal Dementia Alzheimer’s disease, retrograde transport of this protein is disrupted in Pick’s (FTD) and Amyotrophic Lateral Sclerosis (ALS). In the present study we disease, which supports the hypothesis that tau dysfunction interferes with used immunofluorescence and deconvolution microscopy to examine the retrograde transport of proNGF. make-up and structure of ubiquitinated inclusions in sporadic ALS. Using fixed, paraffin-embedded, 6 micron thick spinal cord tissue sections from ALS cases, we labelled for ubiquitin and TDP-43. In accordance with 220 D304 previous immunohistochemical studies, ubiquitin and TDP-43 appeared to LONG-TERM CHANGES IN NEUROTROPHIC FACTOR co-localize in both skeins and round inclusions in our 2D images. When we EXPRESSION IN DISTAL NERVE STUMP FOLLOWING MUSCLE examined the inclusions in 3-D there appeared to be areas of ubiquitin and DENERVATION AND REINNERVATION WITH MOTOR OR TDP-43 co-localization in the skeins, whereas the round inclusions appeared SENSORY NERVES to have a ubiquitin core, surrounded by TDP-43. Furthermore, 3-D imaging * Bernadeta Michalski(1), James R. Bain(2), Margaret Fahnestock(1). revealed that ubiquitinated round cytoplasmic inclusions may be formed (1)Department of Psychiatry and Behavioural Neurosciences, (2)Division of through a dynamic process, where ubiquitinated skeins eventually become Plastic Surgery, Department of Surgery, McMaster University, Hamilton, round inclusions and such neuronal inclusions exist at various stages of Ontario compaction throughout the spinal cord of affected individuals. The present study illustrates the importance of the use of 3-D imaging Following peripheral nerve injury, Schwann cells of the distal nerve techniques, which enabeled us to further examine the physical interaction of stump acutely alter expression of neurotrophic factors, which may contribute the protein components of ubiquitinated inclusions in ALS. This, in turn, to a stimulating environment for nerve regeneration. However, over time, the may offer clues to disease pathogenesis. skeletal muscle atrophies and loses receptivity to the regenerating axon. A sensory nerve sutured to the distal nerve stump during prolonged denervation significantly improves distal nerve stump and skeletal muscle morphology 222 D306 and functional recovery and modulates neurotrophic factor levels in muscle. ALTERED STOICHIOMETRY OF NOVEL HUMAN PERIPHERIN In this study we investigated whether the sensory nerve also alters SPLICE VARIANT EXPRESSION CAUSES AGGREGATION neurotrophic factor expression in distal nerve stump. In our model, rat tibial Shangxi Xiao and Janice Robertson. Centre for Research in nerve (mixed motor and sensory components) is transected and either left Neurodegenerative Diseases, University of Toronto denervated (“denervated group”) or the peroneal nerve (mixed nerve, “immediate repair group”) or the saphenous nerve (pure sensory nerve, The intermediate filament protein peripherin is a component of axonal “sensory protection group”) is sutured to the distal stump. The intact tibial spheroids and of Lewy-body like inclusions in amyotrophic lateral sclerosis nerve is used as a control. Our results demonstrate that denervated distal (ALS). Three peripherin mRNA transcripts generated by alternative splicing stump expresses mRNA for all investigated neurotrophic factors, BDNF, have previously been identified in mouse and we have shown their NGF, NT-3, GDNF and CNTF, for at least six months following injury. differential expression in transgenic models of ALS. Here we describe a BDNF and GDNF mRNA levels rise dramatically in distal stump for the first novel human peripherin transcript, Per 3,4, that retains introns 3 and 4. A month following denervation. By two to three months after injury, BDNF predicted protein species of ~27.6 kDa is expressed from the Per 3,4 and GDNF levels have begun to fall, but they remain elevated above control transcript in transfected SW13 vim(-) cells. We show that the Per 3,4 levels for at least six months. Sensory protection significantly lowers injury- transcript is also expressed from the normal human peripherin gene and that induced BDNF and GDNF mRNA levels in distal stump compared to changes in the stoichiometric ratio of peripherin splice variant expression can denervated distal stump, whereas motor nerve repair is lower still and not lead to peripherin aggregate formation. Using a unique peptide sequence significantly different from controls at any time. In contrast to BDNF and created by intron 3, we made an antibody specific for Per 3,4. Here we GDNF, CNTF levels are down-regulated with injury and remain at low levels provide evidence for the expression of Per 3,4 in human ALS spinal cord for at least 6 months in denervated distal stump, returning towards control tissues and also show an upregulation of the Per 3, 4 message in ALS RNA levels in distal stump repaired with motor nerve, and exhibiting a trend samples. These findings suggest that alternative splicing of peripherin occurs towards normal levels of CNTF mRNA in the sensory protected group. in ALS and may contribute to disease pathogenesis. Sensory protection did not affect mRNA expression of NGF or NT-3 These data demonstrate a role for sensory protection in altering neurotrophic factor mRNA expression in distal nerve stump following motor denervation and 223 D307 demonstrate the ability of the distal nerve stump to contribute to a DELINEATION AND VALIDATION OF THE SUB-CELLULAR neurotrophic environment for nerve regeneration for at least six months. MECHANISMS UNDERLYING CELL DEATH IN PARKINSON’S Furthermore, BDNF and GDNF may serve as biomarkers of successful DISEASE USING A CELL MODEL communication between nerve and muscle. Christopher J. Yong-Kee*, Asad Hanif, Joanne E. Nash

Idiopathic Parkinson’s disease (PD) is thought to be caused by many 221 D305 individual cellular abnormalities such as oxidative stress, mitochondrial TDP-43 INCLUSIONS IN ALS: INSIGHT GAINED THROUGH dysfunction and a malfunctioning ubiquitin-proteasome system (UPS). THREE DIMENTIONAL ANALYSIS Increasing evidence has shown that a combination of interactions between Teresa R. Sanelli, Shiangxi Xiao, Patrick Horne and Janice Robertson. each of these individual abnormalities causes cellular death. Indeed, using Centre for Research in Neurodegenerative Diseases, Tanz Neuroscience pharmacological tools, we have shown that inhibition of mitochondria, UPS Building, University of Toronto and lysosome function interact synergistically to decrease cell viability. Given that multiple mechanisms are responsible for cell death in PD, and that TAR DNA binding protein (TDP-43) is a 43 KDa protein that was first these pathways synergise, development of an effective neuroprotective identified as a DNA binding protein of the human immunodeficiency virus 1 strategy requires elucidation of how these sub-cellular mechanisms interact. long terminal repeat (HIV-1 LTR). Although it has no known physiological To this end, we utilized the dopaminergic neuroblastoma cell line, SH-SY5Y function in neuronal cells, it is a nuclear protein known to be involved in and determined the expression of proteins linked with neurodegeneration in transcriptional repression and regulation of alternative splicing. Recently, PD through SDS-PAGE followed by Western blotting and immuno- TDP-43 was found to be a major component of pathological neuronal cytochemistry. SH-SY5Y cells were exposed to EC50 concentrations of

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toxins which recapitulate cell death in PD - dopamine (300 μM) EXCITABILITY, SYNAPSES & GLIA: (reactive oxygen species), excitatory cocktail [KCl (30 mM), glycine (30 μM) and NMDA (100 μM)] (excitotoxicity), naphthazarin (7.26 CELLULAR MECHANISMS μM) (lysosome damage), proteasome inhibitor (PSI) (40 μM), and rotenone (10 μM) (mitochondrial complex 1 inhibition). Twenty four hours following exposure to toxins, α-synuclein, caspase-3 and 226 A201 ubiquitin levels were examined by either Western blotting of cell lysates or CRITICAL ROLE FOR CREB ACTIVATION IN immunocytochemistry of fixed cells. An interaction between mechanisms is NEUROPROTECTION BY NMDAR-PSD95 UNCOUPLING seen when two proteins, e.g. α-synuclein and ubiquitin are increased Joan Forder (1), Michael Tymianski (1), Michelle Aarts (2). 1 - Toronto by a toxin (PSI) application which would be expected to increase only Western Hospital 2. - University of Toronto ubiquitin levels. To validate the use of SH-SY5Y cells to study the mechanisms underlying cell death in PD, the neuroprotective potential of Studies indicate that specific intracellular signal pathways linked to N- several compounds was evaluated in SH-SY5Y cells exposed to toxins which Methyl D-Aspartate Receptors, rather than receptor activation itself, are recapitulate cell death mechanisms in PD. Salicylic acid (10 mM, 1mM), responsible for determining excitotoxic neuronal death in stroke. As proof of caffeine (10 mM, 1mM), nicotine (10 μM, 1 μM), creatine (25 principle, success has been made in rodent models of stroke using cell- mM, 10 mM) coenzyme Q10 (117 μM, 35 μM) and L-deprenyl permeable peptides that uncouple NMDARs from binding to PSD95, an (10 μM, 1 μM) were added to cells 5 minutes prior to addition intracellular scaffold protein that mediates multiple protein-protein of dopamine (30 μM), excitatory cocktail [KCl (30 mM), glycine (30 interactions and brings intracellular second messengers in close μM) and NMDA (100 μM)], naphthazarin (2.17 μM), approximation to receptors. Uncoupling PSD95-NMDAR interactions proteasome inhibitor (PSI) (40 μM), or rotenone (10 μM). Cell provides long-term (2 months) neuroprotection and functional recovery in viability was assessed after 24 hours using the redox-sensitive dye, Alamar animal models of stroke, a property not before demonstrated for a stroke BlueTM. The neuroprotective potential of each drug is determined by therapeutic. Pharmacologic blockade of NMDARs however provides only comparing with toxin alone. These studies will determine the interactions short-term (24h) benefits and limited functional recovery. Blocking between cellular mechanisms which cause PD, as well as validating this cell NMDAR-PSD95 interaction reportedly impedes cell death by blocking the model, so that it may be used to assess novel potential neuroprotective production of the toxic free radical, nitric oxide (NO). This is likely an treatments in the future. overly simplistic view of neuroprotection as PSD95, and the NMDAR itself, govern multiple signals necessary for glutamate receptor communication and neuronal survival including calmodulin (CaM) and Ras-MAP kinase-linked 224 D308 signal cascades. If neuroprotection were conferred simply by blocking PSD- ABSTRACT WITHDRAWN. 95 associated signals (such as NO production) then pharmacologic blockade should also be effective. With this dichotomy in mind we hypothesized that neuroprotection requires not only a blockade of toxic signals but that a ‘normal’ balance of NMDAR signalling is restored during anoxic stress. Here we show that CREB, a nuclear transcription factor phosphorylated EDUCATION downstream of CaM and MAP kinases, plays a key role in neuroprotection by uncoupling NMDARs from PSD95. CREB phosphorylation, activated in response to NMDA or oxygen glucose deprivation (OGD), is maintained for 225 A401 a longer period of time in cells treated with a peptide inhibitor of the BEHAVIORAL NEUROSCIENCE IN ONLINE EDUCATION NMDAR-PSD95 interaction (TAT-NR2B9c), a result paralleled by * John Medaglia, Nicole Sestito, Felipe Da Silva, and Douglas Chute, PhD.. neuroprotection by TAT-NR2B9c in both NMDA excitotoxicity and OGD Drexel University, The University of Pennsylvania experiments. In addition, in vivo neuroprotection by TAT-NR2B9c was blocked by concomitant application of KN-93, a CaM-kinase IV & II Technology is continually being applied in new and innovative ways to blocker. CaM-kinase IV is a nuclear kinase that directly phosphorylates education in the sciences at all levels. For the first time at Drexel University, CREB and its binding protein. Thus, manipulating neuroprotective NMDAR an online ePsychology program has been initiated and one of the debut signalling in combination with uncoupling PSD95 may yield new therapeutic classes offered is Behavioral Neuroscience. This poster will present some of strategies for neuroprotection in excitotoxic disease. the techniques used in this course to overcome some of the hardships often associated with long-distance learning, and discuss how distance learning may be advantageous in some respects. Focuses of the poster will include 227 A202 methods and quality of student to student and student to professor A PHYSIOLOGICAL ROLE FOR PHOSPHATIDIC ACID AND THE communication, how problems were handled as they arose, how experiments PATTERN OF STIMULATION IN THE TRANSLOCATION OF THE were conducted without a physical classroom, and the results of a class NOVEL PROTEIN KINASE C APL II IN APLYSIA NEURONS gender difference experiment. A student project using modern video and Carole Abi Farah*, Xiaotang Fan and Wayne S. Sossin. The Department of audio technology to describe neural transmission and Drexel’s collaboration Neurology and Neurosurgery, Montreal Neurological Institute, McGill with the University of Pennsylvania will also be discussed. Possible future University, Montreal developments of the online program will be included as well as subsequent research planned to determine the efficacy of the methods of education used. Protein kinase Cs are important mediators of synaptic plasticity. In Aplysia, serotonin-mediated activation of PKC Apl II is important for some forms of synaptic facilitation. Calcium-independent or novel PKCs (nPKCs) such as PKC Apl II contain an N-terminal C2 domain, but the role of this domain is controversial. Using live-imaging of fluorescently-tagged fusion proteins of PKC Apl II and PKC Apl II ΔC2 in Sf9 cells and primary sensory neurons of Aplysia, we demonstrate that the role of this domain in nPKCs is inhibitory. Moreover, we show that phosphatidic acid, generated by phospholipase D, removes C2 domain-mediated inhibition of PKC Apl II and is required for the physiological translocation of PKC Apl II by serotonin in

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sensory neurons. While imaging the physiological translocation of PKC Apl 230 A205 II, we made a surprising observation. Translocation of PKC Apl II is sensitive ADIPONECTIN ACTIONS IN SUBFORNICAL ORGAN to the pattern of stimulation. Spaced applications of serotonin strongly I. Alim and A.V. Ferguson desensitize PKC Apl II translocation, while desensitization is much weaker with prolonged applications of serotonin. PKC activation was not required Adiponectin (ADP) is a peptide produced by adipose tissue, which acts for this desensitization by spaced applications of serotonin. This has as an insulin sensitizing hormone. Recent studies using whole-cell important implications for understanding why these different patterns of electrophysiology in the brain have shown that neurons in both the area stimulation lead to different physiological outcomes and is one possible postrema and the paraventricular nucleus are affected by ADP. We have explanation for differences between spaced and massed training in Aplysia. recently demonstrated that the subfornical organ (SFO), a circumventricular structure responsive to amylin CCK and ghrelin, also shows a high density of mRNA for both adiponectin receptors (AdipoR1, AdipoR2). These 228 A203 observations suggest that SFO maybe a key player in ADP signaling from STRUCTURE-BASED DESIGN, PARALLEL SYNTHESIS, circulation to the brain. Using dissociated SFO neurons maintained in cell STRUCTURE-ACTIVITY RELATIONSHIP AND culture we tested the hypothesis that ADP influences the excitability of SFO ANTICONVULSANT ACTIVITY OF SOME N-SUBSTITUTED neurons. The effects of ADP on membrane potential of dissociated SFO BENZAMIDINE neurons were recorded using whole-cell patch clamp in current clamp mode. Afolabi, E. O.*, Amah, L. O., Okpara, G. and Okolie V. Department of ADP had clear effects on the excitability of SFO neurons which either Pharmaceutical Chemistry, University of Jos, Jos. Nigeria depolarized (14.5 ± 3.4 mV, 9 of 23 cells) or hyperpolarized (-8.4±1.1 mV, 8 of 23 cells) following exposure to 10nM ADP. These observations indicate The anticonvulsant activities of some analogues of N-substituted that ADP does play a role in modulating SFO ionic channels, suggesting that benzamidines were determined at three dose levels in accordance with the the SFO may play roles in sensing circulating concentrations of ADP and Antiepileptic Drug Development Program (ADD) of National Institute of transmitting such signals to essential hypothalamic autonomic control Health (NIH), USA. These compounds are analogues of 4-amino-N-(2,6- centers. dimethylphenyl)benzamide (Ameltolide ®), (LY201116) which is the most potent benzamide anticonvulsant studied to date. The benzamidines were designed as prodrugs of Ameltolide by isosteric replacement of the carbonyl 231 A206 oxygen with amidine (NH) group. The in-vivo metabolism of benzamidines REAL-TIME VOLUME RESPONSES OF ASTROCYTES TO to benzamides seems to improve anticonvulsant properties. OSMOTIC AND ISCHEMIC STRESS IN CORTICAL BRAIN SLICES Sergei A. Kirov, R. David Andrew*. Dept Neurosurgery, Medical College of 229 A204 Georgia, Augusta, GA; Centre for Neuroscience Studies, Queen’s University, TRANSIENT CHOLINE-MEDIATED DEPRESSION OF SYNAPTIC Kingston TRANSMISSION IN HIPPOCAMPAL SLICES Tarun Ahuja*, John G. Mielke, and Geoffrey Mealing. Neurobiology Studies of how acute osmotic challenge affects the volume of cortical Program, Institute for Biological Sciences, National Research Council of neurons and glia have concentrated on isolated or cultured brain cells. Two- Canada, Ottawa photon laser scanning microscopy (2PLSM) enables real-time visualization of functioning cells expressing Green Fluorescent Protein (GFP) deep (60- Nicotinic acetylcholine receptors (nAChRs) are pentameric, ligand-gated 200 µm) within living neocortical and hippocampal slices. Using 2PLSM we ion channels formed from various alpha (α2-10) and beta (β2-4) recently showed that pyramidal somata, dendrites and spines steadfastly subunits, and modulate network activity in the brain as a consequence of maintain their volume during osmotic stress, as do cerebellar axon terminals broad cholinergic innervation. While the variety of subunits allows for (Andrew et al., Cerebral Cortex, in press). Here we use similar techniques to numerous functional combinations, one predominant type is the α7 monitor changes in astrocytic volume within hippocampal slices (400 um) homopentamer (α7 nAChR), which is highly permeable to Ca2+ and from 37-40 day old mice of the FVB/N-Tg(GFAPGFP)14Mes/J strain. thought to influence both memory and neurodegeneration. Choline, a Single astrocytic cell bodies, their processes and capillary end-feet display selective agonist of α7 nAChRs, is present in the synaptic cleft after GFP fluorescence (Zhuo et al. 1997, Devel. Biol. 187,36-42). Volume degradation of acetylcholine, but little has been done to try and understand responses to 20 min of overhydration (-40 mOsm) or dehydration (+40 or how it may affect synaptic transmission. Using extracellular recordings from +80 mOsm) were measured in astrocytic cell bodies and their processes acutely prepared brain slices, we attempted to determine the effects of (n=15 slices). Astrocytes reversibly swelled during overhydration and shrank exogenously applied choline upon synaptic activity in the dendritic region of during dehydration. These same astrocytes also rapidly swelled during the hippocampal CA1 subfield. Our results show that bath application of O2/glucose deprivation (OGD) for 10 min (as do adjacent pyramidal choline significantly depressed the amplitude of evoked field excitatory post- neurons, Andrew et al., ibid). We then imaged four of these slices during synaptic potentials (fEPSPs) in a concentration dependant manner (10, 500, recovery from OGD. Within 10 min, astrocytic volume recovered by 100% and 1000 μM). Furthermore, the depression developed within minutes, in 4 slices and by 80% in 4 others. Such recovery did not occur in adjacent and was reversed upon washout, albeit incompletely following the highest pyramidal neurons which remained swollen with beaded dendrites post- choline concentration. Given that choline (500 μm) did not affect OGD. We conclude that, in contrast to pyramidal neurons, adjacent measures of presynaptic function such as paired-pulse facilitation and astrocytes are clearly osmoresponsive to acute osmotic stress. We have not stimulation-response curves, we believe that a postsynaptic mechanism is yet detected evidence for astrocytic volume regulation during acute responsible for the observed depression. In order to confirm the role of challenge. Simulated ischemia induces an immediate and dramatic swelling α7 nAChRs, two different specific antagonists were used. Surprisingly, of astrocytes upon onset of anoxic depolarization. Unlike adjacent pyramidal neither methyllycaconitine, nor α-bungarotoxin was able to completely neurons that also swell, astrocytes display significant recovery from prevent the choline-mediated effect upon evoked fEPSPs. Future O2/glucose deprivation. experiments will attempt to clarify the underlying mechanism of choline- mediated depression by administering additional subtype-specific nAChR antagonists, and examining interactions with depression caused by low- frequency stimulation.

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232 A207 despite the fact that ASIC current amplitudes and kinetics are very similar in PROTEIN KINASE G INHIBITION RAPIDLY CONFERS ACUTE wild-type, heterozygous, and homozygous parkin KO mice. These findings STRESS PROTECTION IN NEURAL CIRCUITS implicate parkin, for the first time, in the functional regulation of an ion Gary A.B. Armstrong*, R. Meldrum Robertson. Department of Biology, channel. Given that ASIC channels contribute to excitotoxic responses to Queen's University brain injury, we propose that defects in parkin-mediated ubiquitination of PICK1 could enhance ASIC channel activity and thereby promote Neural circuits exposed to high but sub-lethal temperatures are impaired neurodegeneration in Parkinson’s disease. Supported by CIHR and Parkinson and cease to function long before cell death. Ectothermic animals such as the Society Canada. migratory locust (Locusta migratoria), which do not possess the ability to regulate their internal temperatures, are particularly susceptible to rapid changes in ambient temperatures. In response to these challenges locusts 234 A209 have developed a strong response to heat stress. Preconditioning treatments MODULATION OF CHOLINE ACETYLTRANSFERASE ACTIVITY (3hr at 45°C followed by 1hr at room temperature; heat shock, HS) switch on BY POLYSIALIC ACID physiological adaptations which subsequently provide protection. Using Alison Burgess(1,2), *Ying-Qi Weng(2), Lamya Shihabuddin(3), Freda ventilatory central pattern generator (CPG) activity as a measure of central Miller(4), Urs Rutishauser (5), Isabelle Aubert(1,2). 1) Department of nervous system function we investigated the role of protein kinase G (PKG) Laboratory Medicine and Pathobiology, University of Toronto, 2) in mitigating neural thermosensitivity to heat stress. Using a semi-intact Sunnybrook Health Sciences Centre, Toronto, 3) Genzyme Corporation, preparation we monitored ventilatory motor pattern activity as saline Framingham, Massachusetts, USA, 4) Department of Molecular and Medical temperature was heated. Prior to circuit failure we observed arrhythmias in Genetics, University of Toronto, 5) Memorial Sloan-Kettering Cancer motor pattern generation. Upon circuit failure we switched off the heat Center, New York, USA source and allowed the preparation to cool, thereby reestablishing conditions for circuit recovery. We scored the prevalence of arrhythmias, failure Choline acetyltransferase (ChAT), the enzyme synthesizing temperatures and recovery times. Using a pressure injection system we acetylcholine, is known to be activated by brain-derived neurotrophic factor delivered agonists and antagonists of the PKG signaling pathway directly (BDNF). We investigated the possibility that removal of polysialic acid into the ventilator neuropil. Following nanoinjections of the PKG antagonist (PSA) on embryonic septal neurons, would impact the function of BDNF on KT5823 we found that control animals had high incidence of ventilatory these cells and influence ChAT activity. Interestingly, we found that the arrhythmias (60%) whereas treated animals had lower prevalence (13%). removal of PSA using endoneuraminidase N (endoN), significantly increased Circuit thermotolerance (failure temperature) was extended from 38°C to BDNF-induced ChAT activity. PSA removal did not influence cell survival 47°C and the length of time taken to recover was reduced from 180 to 47 and the number of cholinergic neurons present in culture. In these conditions, seconds. Conversely, HS animals which have protective physiological ChAT activity was unaltered by the removal of PSA alone (in absence of adaptations already switched on were more susceptible to thermal insults BDNF), or the application of antibodies blocking the function of to the neural following injections of the PKG agonist 8-Bromo-cCMP. We observed a cell adhesion molecule (NCAM). BDNF-induced ChAT activity required the higher incidence of ventilatory arrhythmias (40% vs. 15%), a reduced failure stimulation of both BDNF’s receptors, namely the p75 neurotrophin receptor temperature (36°C vs. 47°C), and longer recovery time (147 seconds vs. 75 and the tropomyosin related kinase B receptors. Mechanistically, PSA seconds) then their HS counterparts. These data indicate that PKG plays an removal increased the maximal binding capacity of [125I]BDNF to its integral role in modulating stress protection in neural circuits. receptors, suggesting that this additional binding of BDNF upon PSA removal maximizes ChAT activity. We are investigating the signaling mechanisms activated by BDNF, and combined with PSA removal, which 233 A208 trigger ChAT activity. Furthermore, we established that PSA removal in PARKIN-MEDIATED UBIQUITINATION OF THE PDZ PROTEIN presence of BDNF promotes a cholinergic phenotype in immature cells PICK1 REGULATES ACID-SENSING ION CHANNEL ACTIVITY derived from the adult brain. Our results indicate a novel role for PSA in the Ariel R. Ase (*), Monica Joch (*), Xiuqing Chen, Penny A MacDonald, regulation of cholinergic neurons, especially in presence of the neurotrophin Maria Kontogiannea, Amadou T. Corera, Alexis Brice, Philippe Séguéla, BDNF. Edward A. Fon. Montreal Neurological Institute, Dept. of Neurology & Neurosurgery, McGill University, Montreal 235 A210 Mutations in the parkin gene result in an autosomal recessive juvenile- DOPAMINERGIC FUNCTION IN ADULT MICE WITH REDUCED onset form of Parkinson’s disease. Parkin functions as an E3 ubiquitin-ligase NURR1 EXPRESSION that promotes the attachment of the small protein ubiquitin onto specific Baillargeon, J., Paquet B., Lévesque D., Rouillard, C.. Unité de recherche substrate proteins. Defects in the ubiquitination of parkin substrates are en Neurosciences, Centre de recherche du CHUL (CHUQ), Sainte-Foy, therefore believed to lead to neurodegeneration in Parkinson’s disease. Here, Québec, Canada et Faculté de Pharmacie, Université de Montréal we identify the synaptic PDZ protein PICK1 as a novel substrate of parkin- mediated ubiquitination. We find that parkin binds PICK1 via a PDZ- The Nurr1 gene, which codes for a transcriptional factor in the nuclear mediated interaction and promotes PICK1 ubiquitination. Interestingly, receptor superfamily, plays an essential role in the development of parkin-promoting ubiquitination does not seem to target PICK1 to the mesencephalic dopamine (DA) neurons and an important role in the proteasome for degradation. This led us to hypothesize that PICK1 functional maintenance and survival of these neurons. Given its role in the ubiquitination might regulate intracellular trafficking or interactions with development of the DA phenotype, it is conceivable that Nurr1 could also other PDZ ligands. Accordingly, we examined the effect of parkin-mediated play a role in dopaminergic function in the adult brain. Nurr1 homozygotous PICK1 ubiquitination on the previously described PICK1-dependent ASIC2a knock-out (-/-) mice die at birth, probably due to developmental deficiencies potentiation induced by the PKC agonist OAG. We observed that wild-type of the brain stem. However, Nurr1 (+/-) mice are viable, fertile and display parkin, but not PDZ-binding defective or E3 ubiquitin-ligase inactive parkin no apparent deficiencies. These mice have reduced Nurr1 expression mutants, abolishes the OAG-induced PICK1 potentiation of ASIC2a currents throughout their life and decreased levels of DA at 2 months but normalized in transfected COS cells. Native ASIC currents in cultured hippocampal levels at 5 months. The objective of the present study was to investigate the neurons of mice lacking the parkin gene are potentiated following OAG physiological role of reduced Nurr1 expression on the dopaminergic function treatment. This modulation is absent in wild-type hippocampal neurons, in the adult brain. First, we investigated two aspects of DA-mediated locomotor activity; 1) the basal locomotor activity in their home cage as

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measured by a wheel-system, and 2) the amphetamine (AMPH)-induced administration of 6 hydroxydopamine (6 OHDA) to neonatal (P4) rats, a locomotor activity measured in a Flex-Field apparatus. Nurr1 (+/-) mice have significant proportion of surviving neurons of the ventral tegmental area a reduced basal locomotor activity compared to their wild-type (WT) (VTA) contain both tyrosine hydroxylase (TH) and VGluT2 mRNA (Dal Bo littermates. However, there is no difference in the locomotor activity induced et al., 2007, submitted). To seek evidence for the in vivo colocalization of TH by a low dose of amphetamine (2.5 mg/kg i.p.). In the second part of the and VGluT2 protein in axon terminals of DA neurons, we therefore examined study, we investigated the biochemical changes associated with Nurr1- the nucleus accumbens (nAcb) of P15 rats treated or not with 6-OHDA, using reduced expression. As previously reported, Nurr1 expression is reduced by double labeling immuno-electron microscopy with specific antibodies approximately 50% in all brain structures in Nurr1 (+/-) mice. Interestingly, against TH and VGluT2. Doubly (TH /VGluT2) as well as singly (TH or an acute administration of AMPH has no effect on Nurr1 mRNA expression VGluT2) labeled axon terminals were readily identified in the nAcb of both in the SN/VTA complex in WT animals but induces a significant increase in control and 6 OHDA-treated rats. The total number of terminals labeled for Nurr1 (+/-) mice bringing the levels of Nurr1 at the same levels than WT TH was markedly diminished after the 6-OHDA lesion (38% decrease), but animals. Nurr1 mRNA levels in the hippocampus (CA1, CA2 and CA3) are the proportion of dually-labeled terminals slightly but significantly higher significantly upregulated in both heterozygotous and WT mice. As expected, than in controls (37% vs 28%; p < 0.05). As observed in single thin sections, a single AMPH administration induces a significant upregulation of the frequency with which labeled axon varicosities displayed a synaptic enkephalin (ENK) mRNA in the striatum and nucleus accumbens (core and contact was higher for dually (TH/VGluT2) than singly labeled terminals in shell) in Nurr1 (+/+) mice whereas this AMPH-induced upregulation is both control and lesioned rats. When extrapolated to the whole volume of absent in Nurr1 (+/-) animals. Striatal and accumbal dynorphin mRNA levels varicosities, the proportion of TH/VGluT2 terminals making a synapse are not modulated by the acute administration of AMPH in both mouse types. reached almost 100% in both groups, as opposed to respective values of 34% These data suggest that reduction of Nurr1 mRNA levels induces subtle (control) and 55% (lesioned) for terminals labeled for TH only, and 51% changes in DA-mediated neurotransmission. (control) and 73% (lesioned) for terminals labeled for VGluT2 only. These data demonstrate that, in the juvenile rat, many axon terminals of DA neurons projecting to the nAcb have the potential to contain and release glutamate. 236 A211 Moreover, the synaptic or asynaptic character of these axon terminals INTEGRATION OF ASYNCHRONOUSLY RELEASED QUANTA appears to be dependent on their glutamatergic phenotype. Further studies PROLONGS THE POSTSYNAPTIC SPIKE WINDOW will be needed to determine if similar characteristics prevail at maturity, and Karl J. Iremonger, Jaideep S. Bains. Hotchkiss Brain Institute, University of whether they are shared by DA neurons innervating other brain regions, such Calgary as the neostriatum and the prefrontal cortex (Supported by CIHR grants MOP 3544 and NARSAD). Classically, the release of glutamate in response to a presynaptic action potential causes a brief increase in postsynaptic excitability. Recent reports indicate that at some central synapses, a single action potential can elicit 238 A213 multiple, asynchronous release events. This raises the possibility that the MYELIN BASIC PROTEIN IS A MULTIFUNCTIONAL PROTEIN: temporal dynamics of neurotransmitter release may determine the duration of LIPID, ACTIN, AND SH3 DOMAIN BINDING altered postsynaptic excitability. In response to physiological challenges, the Joan M. Boggs*, Godha Rangaraj. Molecular Structure and Function, magnocellular neurosecretory cells (MNCs) in the paraventricular nucleus of Research Institute, Hospital for Sick Children, and Laboratory Medicine and the hypothalamus (PVN) exhibit robust and prolonged increases in neuronal Pathobiology, University of Toronto activity. While the postsynaptic conductances that may facilitate this form of activity have been investigated thoroughly, the role of presynaptic release has Myelin basic protein (MBP), the second most abundant protein in central been largely overlooked. Since the specific patterns of activity generated by nervous system myelin, is responsible for adhesion of the cytosolic surfaces MNCs require the activation of excitatory synaptic inputs, we sought to of multilayered compact myelin. A member of the “intrinsically disordered” characterize the release dynamics at these synapses and determine whether or conformationally adaptable protein family, it also appears to have several they contribute to prolonged excitability in these cells. We obtained whole- other functions. It can interact with a number of polyanionic proteins cell recordings from MNCs in brain slices of p21-44 rats. Stimulation of including actin, tubulin, Ca2+-calmodulin (CaM), and negatively charged glutamatergic inputs elicited large and prolonged postsynaptic events that lipids, and acquires structure on binding to them. It also has a PXXP motif, resulted from the summation of multiple, asynchronously released quanta. predicted to bind to proteins with SH3 domains. It can be modified post- Asynchronous release was selectively inhibited by the slow calcium buffer translationally by phosphorylation and deimination of Arginine to citrulline, EGTA-AM and potentiated by brief stimulus trains. Administration of these resulting in a reduction of its positive charge. An increase in deimination trains also caused a prolonged increase in postsynaptic spike activity that occurs during development and in multiple sclerosis. Extracellular signals could also be eliminated by EGTA-AM. Our results demonstrate that received by myelin or cultured oligodendrocytes cause changes in glutamatergic terminals in PVN exhibit asynchronous release which is phosphorylation of MBP, suggesting that MBP is involved in signaling. We important in generating large postsynaptic depolarizations and prolonged investigated the interactions of MBP with actin and SH3-domain containing spiking in response to brief high frequency bursts of presynaptic activity. proteins, ability to bind these proteins to a lipid surface, and the effect of post-translational modifications of MBP and of phosphorylation of phosphatidylinositol in the lipid bilayer on these interactions in vitro. The 237 A212 ability of MBP to bind actin to a lipid surface is decreased by CaM, by COLOCALIZATION OF DOPAMINE AND GLUTAMATE IN AXON phosphorylation and deimination of MBP, and by phosphorylation of PI, all TERMINALS OF THE NUCLEUS ACCUMBENS changes which can occur during signaling. MBP also bound to several SH3 N. Berube-Carriere *, M. Riad, G. Dal B0, L.-É. Trudeau, L. Descarries.. domains on an array and bound the Fyn SH3 domain to a lipid surface. Thus Departments of Pathology & Cell Biology, Pharmacology and Physiology, it may bind proteins with SH3 domains to the cytosolic membrane surface GRSNC, Faculty of Medicine, Université de Montréal, Montreal, Quebec and/or to the cytoskeleton. Further study of this very abundant protein will reveal how it is utilized by the oligodendrocyte and myelin for different There is increasing data indicating that the vesicular glutamate purposes. transporter 2 (VGluT2) is expressed by mesencephalic dopamine (DA) neurons in vitro and in vivo. Recently, we showed by double in situ hybridization that, 2, 6 and 11 days after the cerebroventricular

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239 A214 terminals, whereas the EphB2 labeling was mostly associated with the CLONING AND CHARACTERIZATION OF PROTEIN KINASE C plasma membrane of dendritic shafts, in hippocampus and cerebral cortex. (PKC) APL III, A HOMOLOGUE OF ATYPICAL PKCS IN APLYSIA Both EphA4- and EphB2-associated SIGP were found on PSD, plasma Joanna Bougie, Carole Abi Farah, Travis Lim, Gino Ferraro, Varsha membrane, and synaptic vesicles. The localization of EphA4 and EphB2 in Manjunath, Darcy Scott, and Wayne S. Sossin. McGill University, Montreal multiple subcellular compartments of neurons suggests that these receptors Neurological Institute interact with distinct proteins and play diverse roles at synapses. Supported by NSERC. D.B. holds a studentship from the Groupe de recherche sur le In Aplysia californica, protein kinase Cs (PKC) are important regulators système nerveux central (Centre FRSQ). of synaptic plasticity and learning and memory. Here, we report cloning and characterization of an additional nervous system isoform of PKC in Aplysia, PKC Apl III, homologous to the non-phorbol ester activated zeta and iota 241 A216 isoforms in vertebrates. PKC Apl III is not activated by phorbol esters, but is IMPAIRED GABAERGIC AND GLYCINERGIC inhibited by chelerythrine, a common PKC antagonist used in many NEUROTRANSMISSION INDUCES REM-SLEEP BEHAVIOUR physiological studies in Aplysia. In vertebrates, a nervous-system specific DISORDER (RBD) IN TRANSGENIC MICE PKM form of PKC zeta, formed from an alternative start codon, plays an Brooks P.L.* (1), Tse G. (1) and Peever J.H. (1,2). (1) Dept. of Cell & important role in synaptic plasticity; however we find no evidence for a PKM Systems Biology, University of Toronto, Toronto (2) Dept. of Physiology, form of Apl III formed by an alternative start site. Interestingly, there is a University of Toronto, Toronto nervous-specific alternatively spliced form of PKC Apl III that provides a calpain cleavage site for formation of a PKM. Confocal imaging of over- Chronic RBD is a neurological disorder that is characterized by excessive expressed Apl III tagged at the N-terminus with mRFP revealed a large phasic muscle activity in REM sleep, which often leads to disturbed sleep proportion of mRFP in the nucleus; however less nuclear staining was seen and physical injury. It is also a harbinger of neurodegenerative disorders, with alternative antibodies to the expressed protein. Nuclear mRFP was not with 80-90% of RBD patients eventually developing Parkinson’s disease or seen with mRFP tagged PKC Apl II or when the same tagged mRFP Apl III other synucleinopathies. Although its cause is unknown, RBD is effectively is expressed in heterologous cells, suggesting specific cleavage of PKC Apl treated with the benzodiazepine clonazepam (a GABAA agonist). This III in sensory neurons, perhaps to a PKM form. Consistent with formation suggests that dysregulation of the endogenous inhibitory processes that of a PKM, an N-terminal antibody to PKC Apl III also showed increased normally suppress phasic muscle activation in REM sleep may underlie the nuclear staining. We are further investigating the mechanism of PKM exaggerated motor activity in RBD. We therefore hypothesize that formation from PKC Apl III through cleavage in the hinge domain. In transgenic mice with impaired GABAA and glycine receptor transmission addition, we are also examining the ability of 5-HT to activate Apl III would have excessive motor activity in REM sleep and therefore exhibit an through translocation or phosphorylation, in Apl III over-expressed sensory RBD phenotype. To test this hypothesis, we used a transgenic mouse model and motor neurons. in which both GABAergic and glycinergic neurotransmission is severely down-regulated (Becker et al., J. Neurosci, 22:2505-12, 2002). To characterize levels of somatic muscle activity, we recorded both EEG and 240 A215 neck EMG activity across the sleep-wake cycle in freely-behaving transgenic PRE- AND POSTSYNAPTIC LOCALIZATION OF EPHA4 AND (Tg, n=4) and wild-type mice (Wt, n=4). While Tg mice have normal sleep- EPHB2 BY SUBCELLULAR FRACTIONATION AND EM wake architecture, they have abnormal motor activity during sleep, and ANALYSIS IN ADULT MOUSE FOREBRAIN particularly in REM sleep. Using both videography and EEG/EMG activity, David Bouvier 1, Tidjane A. Corera 2, Marie-Ève Tremblay 1, Keith K. we observed that all Tg mice exhibited a clear RBD phenotype. They Murai 3, Elena B. Pasquale 4, Miguel Chagnon 5, Edward A. Fon 2, Guy presented with overt periods of vigorous limb movements and jerks. Doucet 1. 1 Département de pathologie et biologie cellulaire, Université de Compared to Wt mice, Tg had a 217% (P=0.016) increase in muscle activity Montréal, Montréal ; 2 Department of Neurology and Neurosurgery and during REM sleep. Although basal levels of muscle activity were similar in Montreal Neurological Institute, McGill University, Montréal; 3 Centre for Tg and Wt mice during both waking and NREM sleep, all Tg mice had Research in Neuroscience, Montreal General Hospital, McGill University, regular myoclonic twitches in NREM sleep. We conclude that: 1) Montreal; 4 The Burnham Institute for Medical Research, La Jolla, CA; 5 GABAergic and glycinergic processes regulate motor suppression in both Département de mathématiques et de statistiques, Université de Montréal REM and NREM sleep; and, 2) impaired inhibitory neurotransmission may underlie RBD. EphA4 and EphB2 receptors have been implicated in synaptogenesis, the maturation of dendritic spines, and long term potentiation (LTP), in the postnatal cerebral cortex and hippocampus. They are generally viewed as 242 A217 postsynaptic in adult CNS, although some data also suggest a presynaptic POLYSIALIC ACID REMOVAL INCREASES THE RATE OF localization. To determine the precise distribution of these receptors at NEURONAL MATURATION IN THE ADULT DENTATE GYRUS mature CNS synapses, we used a combination of subcellular fractionation *Alison Burgess(1, 2), Tatsunori Seki(3), Urs Rutishauser(4) and Isabelle and electron microscopic immunocytochemistry in the adult mouse Aubert (1,2). 1) Department of Laboratory Medicine and Pathobiology, forebrain/midbrain. EphA4 and EphB2 were particularly enriched in University of Toronto, 2) Sunnybrook Health Sciences Centre, Toronto. 3) microsomes and synaptosomes. In synaptosomes, they were profuse in the Department of Anatomy, Juntendo University School of Medicine, Tokyo, synaptic plasma membrane fraction, and detectable in the synaptic vesicle Japan. 4) Memorial Sloan-Kettering Cancer Center, New York, New York fraction. In synaptic junctions, EphA4, but not EphB2, remained strongly associated with post-synaptic density (PSD) core proteins, while both were In the adult brain, the presence of the carbohydrate polysialic acid (PSA) found in the presynaptic active zone fraction. At the ultrastructural level, is limited to areas of on-going neurogenesis. For example, newborn neurons immunocytochemistry showed EphA4 mainly associated with axon of the dentate gyrus of the hippocampus express high levels of PSA and terminals and dendritic spines, in hippocampus and cerebral cortex, whereas interestingly, they can develop into mature neurons and form new neuronal EphB2 was mostly dendritic. EphB2 was, however, more frequent in axon circuits. In this study, we use endoneuraminidase N (endoN) to specifically terminals and dendritic spines in the ventrobasal thalamus. Consistent with cleave PSA in the hippocampus and examine the impact of PSA removal in the fractionation results, silver-intensified immunogold particle (SIGP) adult hippocampal neurogenesis in vivo. EndoN was injected into the labeling for EphA4 was associated mainly with synaptic vesicles, in axon anterior hippocampus followed by intrapertioneal injections of 5-bromo-2’-

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deoxyuridine (BrdU) two days later. EndoN effectively removed PSA in the would similarly confer constitutive activity to the neuropeptide Y1 receptor, hippocampus for at least nine days post-injection, the longest time point two Y1 receptor mutants with either a T258(6.30)A or N262(6.34)A point- tested. Within three days of a BrdU injection, BrdU-positive newborn cells, mutation were generated. Using both biochemical and electrophysiological are found in clusters in the subgranular zone of the dentate gyrus and most assays, we demonstrate that the wild-type (WT)-Y1 receptor does not express the cell cycle marker, Ki67. In control animals three days after BrdU possess any agonist-independent activation, and that the mutations at locus injection, BrdU-positive cells expressing Ki67 and PSA are found both inside 6.30 or 6.34 do not confer constitutive activity. However, when this TMD6 and outside of the cluster. In endoN injected animals, the number of Ki67- region from the WT-Y1 receptor was replaced with that from the positive cells found outside of the cluster was significantly reduced constitutively active m-opioid receptor (MOR), the resulting chimeric compared to control animals. Seven days after BrdU injection, BrdU-positive receptor – Y1-ICL3-MOR – was shown to be constitutively active. cells express immature (double cortin) and mature (neuronal nuclei, NeuN) Constitutive activity expressed by the Y1-ICL3-MOR chimera implicates a neuronal markers in control and endoN injected animals. Interestingly, role for the TMD6 in constitutive GPCR activation and highlights a endoN treated animals have a significant increase in the number of mature significant structural difference between the Y1 receptor and other neuronal cells positive for both double cortin and NeuN, compared to rhodopsin-like GPCRs. We concluded that 1) the activation mechanisms controls. The main findings of this study indicate that PSA favors the identified from the rhodopsin model are not comprehensive for all GPCRs; migration of newborn cells from clusters and that PSA controls the 2) these mechanisms do not regulate the activation of the Y1 receptor; and 3) maturation of newly generated neurons. the TMD6 of the Y1 receptor confers conformational constraints upon the receptor structure that are uniquely resistant to constitutive activation. Supported by CIHR MT10250. WFC is a Medical Scientist of the Alberta 243 A218 Heritage Foundation for Medical Research RESISTANCE OF PRESYNAPTIC CALCIUM CHANNELS (CAV2.2) TO VOLTAGE-DEPENDENT INACTIVATION: DYNAMIC PALMITOYLATION AND VOLTAGE SENSITIVITY 245 A220 Allen W. Chan*, Steven Owens, Connie Tung and Elise F. Stanley. Division SYNAPTIC ACTIVITY AND TRIPHENYLTETRAZOLIUM of Genetics & Development, Toronto Western Research Institute, University CHLORIDE METABOLISM ARE CORRELATED AFTER Health Network, Toronto OXYGEN-GLUCOSE DEPRIVATION IN ACUTE, BUT NOT CULTURED, HIPPOCAMPAL SLICES Presynaptic CaV2.2 (N type) calcium channels gate the influx of calcium Tanya Comas*, John G. Mielke, Tarun Ahuja, Edward Preston, and Geoffrey ions to trigger transmitter release. We have previously demonstrated at the A.R. Mealing. Neurobiology Program, Institute for Biological Sciences, chick ciliary ganglion presynaptic calyx terminal that the bulk of these National Research Council of Canada, Ottawa channels are highly resistant to voltage dependent inactivation. Recent studies have suggested that CaV2.2 can be rendered inactivation-resistant The importance of the hippocampus to learning and memory has attracted when expressed with the palmitoylated beta2A subunit and that this effect significant attention regarding how the structure responds to damage. can be eliminated by tunicamycin, a general inhibitor of dynamic Although many studies have used either the acute hippocampal slice palmitoylation. We find that while tunicamycin treatment had no effect on preparation (AHSP) or organotypic hippocampal slice cultures (OHSC), little CaV2.2 current in the inactivation-sensitive isolated chick dorsal root work has been done to examine if the choice of model is an important ganglion (DRG) neuron, it caused a 10 mV hyperpolarized shift in the profile variable. We sought to examine whether differences exist in how each model of the inactivation-resistant presynaptic CaV2.2 population. This shift responds to a commonly studied ischemic-like insult, oxygen-glucose occurred without any effect on the voltage sensitivity of the inactivation deprivation (OGD). Following OGD, synaptic activity was examined by process, as measured by a Boltzmann slope factor. While these findings recording orthodromically evoked CA1 subfield responses, while suggests that dynamic palmitoylation contributes to the inactivation mitochondrial activity was assessed by spectrophotometric measurement of resistance of presynaptic CaV2.2 can not fully account for the differences formazan produced by metabolism of 2,3,5-triphenyltetrazolium chloride between the somatal and presynaptic Ca channel biophysical properties. (TTC). The insult significantly decreased both synaptic and mitochondrial activity within AHSPs, but a disparity existed between these measures in OHSCs. While evoked activity was greatly reduced by a moderate duration 244 A219 of OGD, a much longer period was required to cause a comparable decrease RESISTANCE OF NEUROPEPTIDE Y1 RECEPTOR TO in TTC metabolism. Quantitative immunoblotting revealed that one possible MUTAGENIC INDUCTION OF CONSTITUTIVE ACTIVITY IS explanation for the discrepancy was an elevated OHSC expression of OVERCOME BY TMD6 CHIMERIZATION astrocytes, which are resistant to OGD. Our data indicate that acutely Melissa JS Chee (1), Kristin Friebel (2), Nicole Merten (2), Peter E Light (3), prepared and cultured slices respond differently to OGD, and suggest that Gerald W Zamponi (4), Annette G Beck-Sickinger (2), William F Colmers assays examining viability in these models must consider such innate (1,3). (1) Centre for Neuroscience, University of Alberta. (2) Institute of differences. Biochemistry, University of Liepzig, Germany. (3) Department of Pharmacology, University of Alberta. (4) Department of Phyisology and Biophysics, University of Calgary 246 A221 MECHANISM OF NEUROPROTECTIVE ACTION OF THE PSD-95 Neuronal receptors are generally considered to be silent in the absence of INHIBITOR TAT-NR2B9C an agonist, but constitutively active G-protein coupled receptors (GPCRs) H. Cui1,2, A. Hayashi1, M. M. Aarts1, M. P. Belmares3, D. Garman3, P. S. can produce a receptor signal even in the absence of agonists. Based on Lu3, M. Tymianski1,2;. 1Division of Applied and Interventional Research, structural studies of crystallized rhodopsin, the activated state of a receptor Toronto Western research Insititute, Toronto, ON, CANADA, 2NoNO Inc., can be encouraged by the loss of intramolecular conformational constraints NoNO Inc., Toronto, 3Arbor Vita Corporation, Arbor Vita Corporation, involving transmembrane domain (TMD) 6. Specifically, site-directed Sunnyvale,, CA mutagenesis of loci 6.30 and/or 6.34 has resulted in generation of constitutively active mutants. It has therefore been proposed that interactions NMDA receptors (NMDARs) interact with the PDZ-domain-containing with these loci may represent a common mechanism for constitutive activity scaffolding protein PSD-95. Perturbing this interaction with a cell-permeable among GPCRs. To test the hypothesis that mutations at these TMD 6 loci peptide that recapitulates the C-terminus of NMDAR 2B subunit (Tat- NR2B9c) reduces neuronal nitric oxide production, excitotoxic vulnerability,

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and stroke size in rats (Aarts et al., Science, 2002). However, the human 248 A223 genome contains >250 unique PDZ domains, raising the possibility that Tat- IMPLICATION OF THE CHEMOKINE MCP-1/CCL2 IN SPINAL NR2B9c may protect neurons through other PDZ-domain interactions. To NOCICEPTIVE determine the mechanism of action of Tat-NR2B9c, its interactions with all NEUROTRANSMISSION known human PDZ domains were determined using a ELISA-based assay for MA Dansereau*3, RD Gosselin1, C Valera1, M Pohl2, P Mechighel1, W which all PDZ domains were cloned and expressed as GST:PDZ fusion Rostene1, P Kitabgi1, S. Melik Parsadaniantz1 & P. Sarret3. 1Unité mixte proteins. The interactions of nNOS with all human PDZs were similarly 732 INSERM-UPMC, Hopital Saint Antoine, Paris, France; 2Unité mixte tested. These screens revealed that Tat-NR2B9c interacts strongly with 5 713 INSERM-UPMC, Faculté de Médecine Pitié-Salpêtrière, Paris, France; PDZ containing proteins: PSD-95, PSD-93, SAP-97, SAP-102 and TIP1. 3Dept. Physiologie & Biophysique (FMSS) Université de Sherbrooke, Moreover, nNOS interacted with PSD-95, PSD-93, SAP-97 and Syn1 Alpha. Canada The EC50s of these interactions were also studied, as well as their inhibition by Tat-NR2B9c. The IC50 of Tat-NR2B9c for inhibiting the interactions An increasing number of studies describe the roles played by chemokines between PSD95:nNOS and PSD95:NR2 subunits was ~0.2 uM, and 0.5- in the central nervous system. Here, we investigate the implication of the 8uM, respectively. To determine which of the observed interactions may play chemokine MCP-1/CCL2 in spinal nociceptive neurotransmission in the rat a role in the neuroprotective mechanism of Tat-NR2B9c, the expression of both in normal and pathological conditions. We show that the MCP-1/CCL2 PSD-95, PSD-93, SAP-97, SAP-102 and nNOS in cultured cortical neurons is constitutively expressed by nociceptive sensory neurons in the dorsal root was inhibited by transfecting them with small interfering RNA duplexes ganglion (DRG), especially nociceptors and in the superficial layers of the (siRNA) targeted against each of these proteins. The neurons were then spinal cord. Using a subcellular fractionation approach, we show that MCP- subjected to NMDA toxicity in order to determine the role of each protein in 1/CCL2 is enriched in large vesicles and that potassium-triggered their vulnerability to excitotoxicity. Only neurons lacking PSD-95 or nNOS, depolarization evokes calcium-dependent release of MCP-1/CCL2 from but not neurons lacking PSD-93, SAP-97 or SAP102 exhibited a reduced DRG or spinal explants. In addition, we demonstrate that CCR2, the vulnerability to NMDA toxicity. Collectively, our data indicate that preferred CCL2 receptor, is expressed in spinal cord neurons of healthy rat NMDAR-dependent excitotoxicity is mediated via the interactions of and that exposure of cultured spinal neurons to MCP-1/CCL2 leads to a dose- NMDAR subunits with PSD-95, and not other PDZ-domain containing dependent inhibition of GABA-induced currents. Finally, we report that a proteins. Neuroprotection by Tat-NR2B9c is thus likely due to its ability to single intrathecal injection of MCP-1/CCL2 (1µg) induces allodynia dissociate NMDARs from nNOS both by inhibiting NR2:PDS95 and mechanism from 2 hours to 6 days post injection in normal rat. Moreover, we PSD95:nNOS interactions. observed that this treatment is also responsible for thermal hyperalgia from 90 to 240 min post injection in hot plate test (52°C). These data suggest that the chemokine MCP-1/CCL2 might be a nociceptor-expressed 247 A222 pronociceptive neuromediator and strongly strengthen the recent concept that GLUTAMATE RECEPTOR SUBUNIT INCREASE IN THE the chemokines represent a new class of neuromodulators. GLOMERULAR LAYER OF THE OLFACTORY BULB MAY SUPPORT MEMORY IN ODOR PREFERENCE LEARNING IN NEONATAL RATS 249 A224 Wen Cui, Andrea Darby-King, Carolyn W. Harley, John H. McLean. CHRONIC AND ACUTE ALTERATIONS OF DROSOPHILA Division of BioMedical Sciences and Dept. of Psychology, Memorial FREQUENINS REVEAL THEIR ROLES IN SYNAPTIC University of Newfoundland, St. John's, NL TRANSMISSION AND NERVE TERMINAL MORPHOLOGY J.S. Dason*, J. Romero-Pozuelo, A. Ferrús, H.L. Atwood. 1. Physiology, Phosphorylation of the AMPA receptor GluR1 subunit has been reported University of Toronto 2. Instituto Cajal, CSIC, Madrid, Spain to be important for the stability of LTP (Lee et al. 2003; Whitlock et al. 2006). This phosphorylation-induced increase of synaptic receptors was critical for Frequenin (Frq) and its mammalian homologue, neuronal calcium sensor potentiating synaptic transmission and is proposed as a mechanism 1, are calcium-binding proteins which enhance neurotransmitter release and underlying the LTP stability. In odor preference learning in neonate rats, we facilitation. Here, we report the discovery of a second Frq-encoding gene hypothesize that phosphorylation of the AMPA receptor GluR1 subunit (frq2) in Drosophila. The temporal and spatial expression patterns of the two induces AMPA receptor increases in the glomerular layer of the olfactory genes are very similar, and the proteins they encode, Frq1 and Frq2, are 95% bulb. This area is where the axons of the olfactory sensory neurons synapse identical in amino acid sequence. We used the Gal4/UAS system to with the dendrites of mitral cells, the major output neurons in the olfactory overexpress Frq1, Frq2 or both in the nervous system. Nerve-evoked bulb. This increase in AMPA receptors would help support memory. excitatory junction potentials (eEJPs) of Frq1 and/or Frq2 overexpressers Previously, we reported that under learning conditions (odor + 2mg/kg were significantly larger than in controls, due to a 1.4 to 2-fold increase in isoproterenol), PKA phosphorylation of the AMPA receptor subunit (GluR1) quantal content at individual synaptic boutons. One of the two motor neurons at serine 845 increased from the end of training to 30 min after training, (MNSNb/d-Is) innervating abdominal muscles 6 and 7 had fewer synaptic reaching the maximum at 10 min after training. This increase was specific to boutons in Frq1 and Frq2 overexpressers, indicating selective effects on the learning group. However, total GluR1 did not change from the end of neuromuscular junction formation. We used several methods to reduce or training to one day after, as measured using Western Blot analysis of the interfere with the function of Frq: RNA interference; transgenic expression whole olfactory bulb homogenates. To identify whether phosphorylation of of an interfering C-terminal peptide to chronically disrupt interaction of Frq GluR1 induces redistribution of GluR1 and increases GluR1 specifically to with its intracellular targets; and introduction of the same peptide into the synaptic area, instead of the whole bulb, we measured the GluR1 changes presynaptic terminals using a forward-filling method to acutely disrupt Frq's in the glumerular layer by using immunohistochemistry. One day after a 10 effects. Both acute and chronic disruption of Frq's actions caused a 70% min training session, during which peppermint odor was paired with 2mg/kg reduction in quantal content per bouton. The chronic treatment also produced isoproterenol, the GluR1 in trained animals increased significantly, compared more synaptic boutons from MNSNb/d-Is motorneurons. All the effects are to naïve animals. Further learning-specific controls are currently being identical for both Frqs, and are consistent with gain-of-function and loss-of- examined. Our preliminary results suggest that phosphorylation through function genotypes. Overall, there was a 6-fold range in quantal content that cAMP-PKA pathway enhances glutamatergic transmission in the olfactory was observed in response to altered Frq levels and/or activity. We conclude bulb and may be a mechanism underlying the maintenance of odor that Frq has two distinct effects: one on neurotransmitter release, and a preference memory. Supported by CIHR second on the formation of synaptic boutons.

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250 A225 for a desensitization of 5 HT1A autoreceptors under such conditions. In FACILIATION IS SENSITIVE TO THE NUMBER OF OPEN CA addition, several studies have previously documented an uncoupling of 5- CHANNELS BUT NOT THE FLUX PER CHANNEL AT FROG HT1A receptors from their G protein in the NRD (but not hippocampus) of NEUROMUSCULAR JUNCTION (NMJ) rats chronically treated with fluoxetine. Therefore, the most likely Knogler LD, Mitchell R, *Shahrezaei V, Delaney, KR. Dept. of Biology, explanation for our results is that, after repeated internalization and University of Victoria and *Dept. of Physiology McGill University retargetting, functional 5 HT1A autoreceptors have been replaced by receptors uncoupled from their G protein on the plasma membrane of NRD Paired pulse faciliation (PPF) is a ubiquitous phenomenon. Like neurons. The functional regulation of these receptors may thus depend on a transmitter release itself it is dependent upon Ca influx into the presynaptic dynamic balance between their production, activation, internalization and terminal (Katz and Miledi 1967 J. Physiol. 189:535) but there are several recycling to the plasma membrane in inactivated (desensitized) form. distinct differences. For example, facilitation is more sensitive than release (Supported by CIHR grant MOP-3544). to presynaptic addition of Ca buffers with slow forward binding rates. We have explored the effect of changing the flux per open channel, or the number of open channels on facilitation and release by changing Ca(ext) or 252 A227 applying low doses of omega-conotoxin GVIA (w-CTX) while recording SUPPLEMENTAL OXYGEN RESCUES CHRONIC HYPOXIA excitatory junction potentials (ejps) from frog pectoralis muscle. Although INDUCED NEURONAL IMPAIRMENT release is very sensitive to Ca(ext) facilitation is not. Reducing Ca(ext) to Guang-He Fei, Zhong-Ping Feng. Department of Physiology, Faculty of 40% of normal reduced release by more than 16-fold but had no detectable Medicine, University of Toronto, Toronto effect upon PPF and reducing Ca(ext) to 10-20% reduced release by more than 100-fold but PPF was reduced by <10% (n=9). Adding w-CTX (50- Chronic hypoxia is one of the most common pathological processes seen 200nM) to normal (1.8 mM Ca) Ringer reduced release gradually over the in clinic and caused neural disfunction. Although oxygen supplement is a course of 30-60 minutes. PPF was reduced concomitant with blockade of common practice in clinic for patients with severe chronic hypoxia-related release: > 50% when release was reduced 6-fold and > 80% when release disorders, its therapeutic effect remains controversial due largely to a lack of was reduced 10 fold (n=6). The inhibitory effect of w-CTX on PPF was not cellular and molecular evidence of improvement. In this study, we have increased by applying w-CTX in reduced Ca(ext) (40% normal) Ringer investigated the effects of hypoxia and reoxygenation with either 40% O2 or (n=2; see Zengel et al., 1993 Br. Res 61:25) ). Collectively our data suggest 80% O2 on variables of neurobehaviors, hypoxia stress factors and the spatial pattern of Ca influx, rather than the total influx has a strong effect presynaptic exocytotic proteins in a simple invertebrate model, fresh water on facilitation at synapses like frog nmj where release is driven by a sparse pond snail Lymnaea stagnalis. We found that chronic hypoxia exposure array of open Ca channels in a linearly extended active zone (Shahrezaei et caused a delayed response of the snail to light stimuli, which coincided with al., 2006 J. Neurosci. 26:13240; Cho and Meriney, Eur. J. Neurosci. a suppression of locomotion activity. Supplement of 40% O2 improved, but 23:3200). Biophysical modeling currently underway suggests facilitation is 80% O2 aggravated the hypoxia-induced neural suppression behaviors. restricted to vesicles in a zone around an open channel that is less than the Semi-quantitative immunoblotting analyses showed that chronic hypoxia length of a single active zone and does not extend to adjacent active zones. exposure induced up-regulation of both HIF-1 This has implications for how neuromodulators that regulate presynaptic Ca and HSP70, was significantly reduced by 40% O2 supplement. 80% O2 activity could differentially affect release and facilitation depending upon the supplement reduced HIF-1 expression, but not HSP70. microgeometry of the active zone at different kinds of synapses. Supported By comparison, O2 supplement prevented the hypoxia induced reduction of by UBC CIHR Neuroscience Training Grant (LK, RM) and NSERC RGPIN presynaptic exocytotic proteins. To determine the long-term effects of O2 121698 supplement, we further studied neural behaviors and the protein levels during the post-O2 supplement periods. We found that both O2 supplements accelerated recovery of the animals from hypoxia induced neural 251 A226 suppression, although 80% O2 caused an initial aggravation of the UNDER CHRONIC FLUOXETINE TREATMENT, FUNCTIONAL 5- symptoms. Immunoblotting analyses showed that O2 supplement groups HT1A AUTORECEPTORS ON THE PLASMA MEMBRANE OF exhibited a rapidly recovery of expression of the proteins detected, as NUCLEUS RAPHE DORSALIS NEURONS ARE REPLACED BY compared to that seen in chronic hypoxia group without O2 treatment. The DESENSITIZED RECEPTORS recovery of protein expression was closely related to neurobehavioral Laurent Descarries *, Mustapha Riad. Departments of Pathology and Cell improvement. In conclusion, our findings provided the direct evidence that Biology and of Physiology, GRSNC, Faculty of Medicine, Université de supplemental oxygen not only improves neurobehavioral dysfunctions but Montréal, Montreal, Quebec rescues altered stress inducible factors and presynaptic proteins induced by chronic hypoxia. Our findings thus support the notion of supplemental The desensitization of 5-HT1A autoreceptors plays a key role in the oxygen is necessary in the treatment of chronic hypoxia-induced antidepressant effects of selective serotonin (5-hydroxytryptamine, 5-HT) neurobehavioral adaptation and impairment. reuptake inhibitors (SSRIs), as these receptors exert a negative control on the firing and hence release of 5-HT neurons. Using quantitative immunogold electron microscopy, we have previously demonstrated an internalization of 253 A228 5-HT1A autoreceptors in neurons (soma-dendrites) of the nucleus raphe MORPHOMETRIC ANALYSES OF DENDRITIC ARBOURIZATION dorsalis (NRD) of rats acutely treated with the SSRI, fluoxetine (Prozac®) OF THALAMOCORTICAL NEURONS IN SOMATOSENSORY AND (Riad et al., 2004). Twenty-four hours after the i.p. injection of fluoxetine, the MOTOR NUCLEI OF THE THALAMUS receptors were back on the plasma membrane of the neurons. Here, we Alex S. Ferecskó*, Reza Zomorrodi, Krisztina Kovács, Igor Timofeev. compared the subcellular localization of 5-HT1A receptors after 1 day and 3 Centre de Recherche Universite Laval Robert-Giffard, 2601 chemin de la weeks of fluoxetine treatment via Alzet minipumps (10 mg/kg/day). After the Canardiere, Quebec 1 day treatment, 5 HT1A receptors were partly internalized in dendrites of the NRD (autoreceptors), but not hippocampus (heteroreceptors). In contrast, The thalmocortical (TC) network is organized in a loop and contributes after the prolonged treatment, the density of dendritic plasma membrane to a variety of sensory and cognitive functions. The main gateway of TC immunolabeling was the same between treated and control rats in both the system is the dorsal thalamus, which receives specific inputs from ascending NRD and hippocampus. This was unexpected in view of the strong evidence sensory pathways. Incoming excitatory inputs terminate on separate

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subcellular compartments along the TC cells dendrites. Prethalamic inputs were selective; KCl increased both expression and import of a physiological occupy predominantly proximal dendrites in contrast, corticothalamic inputs protein mtHSP70 but did not up-regulate Tom20 or GAPDH. Treatment arrive mainly distally. On the intermediate dendrites prethalamic ascending with KCl wholly or partially blocked the inhibitory effects of amyloid beta, and corticothalamic descending inputs overlap. In order to reveal how CCCP and trophic withdrawal on mitochondrial protein import. These dendritic arbor of TC cells provide potential membrane surface for incoming findings demonstrate that in neurons chronic activity up-regulates the synapses, we analysed the dendritic architecture of TC cells in ventral lateral expression of some nuclear encoded mitochondrial proteins and increases (VL) and ventral posterior lateral (VPL) nuclei of the cat. To this end, we their import to mitochondria. Our findings suggest that the KCl mediated used extra- and intracellular neuronal tracing combined with morphometric increase in import is dependent, at least in part, on calcium influx through analyses. Neurons from VPL nucleus were labelled by retrograde transport of voltage gated calcium channels. fluorescent dextrane-amine injected in the somatosensory cortex. VL neuron was visualized using intracellular injection of neurobiotin. Spatial organization of the labelled dendrites was revealed with three-dimensional 255 A230 reconstruction. We found that individual neurons varied considerably in REGULATION OF DOPAMINE SYNAPTIC TRANSMISSION IN overall size and had a mean soma diameter of 32.8±5.3μm. The THE MIDBRAIN labelled cells had usually 6-11 thick dendrites emerging from the soma. The Christopher P. Ford & John T. Wiliams. Vollum Institute, OHSU, Portland, total dendritic length was estimated (mean 16603.7±5075.9μm) and USA showed 2.57 fold differences among the cells. The size of dendritic trees ranged from 315 to 520μm (mean 415±66μm). The thickness of Dopamine (DA) neurons of the Ventral Tegmental Area (VTA) contribute individual dendrites decreased suddenly with increasing distance from the to reward, learning, and are involved in drug addiction and a variety of soma, although dendritic diameter was constant from 4 to 11 dendritic orders mental disorders. In addition to releasing DA at their axon terminals, DA without radical dendritic tapering of the distal segments. The mean diameter cells are also capable of releasing DA from their somas and dendrites. This of 1st order dendrites was 3.5±0.6mm and the last order dendrite was somatodentrically released DA functions to reduce neuronal excitability due 0.8±0.2mm. The number of branch orders of the reconstructed cells ranged to the activation of inhibitory D2 ‘autoreceptors’ and activation of a G- between 2 and 11. Sholl-analysis revealed a peak value of dendritic protein activated inhibitory potassium (GIRK) conductance. Detecting DA bifurcations between 50-90μm from the soma. Our quantitative by classical means using efflux or carbon-fiber amperometry has previously analyses showed that the dendritic area (total mean led to the conclusion that somatodendritically released DA acts in a paracrine 43926.8±16063.7μm2) reached the maximum at 100-150 μm manner (i.e. volume transmission, or ‘spill-over’). However, we have from soma, which corresponds to 5-6th dendritic orders. These findings recently found that that somatodendritically released DA can produce an indicate that the maximal membrane area for incoming inputs is present on 5 inhibitory postsynaptic current (IPSC). The kinetics of this synaptic event and 6 order dendritic branches, where presumably both ascending suggest that within the midbrain, DA may be acting in a manner more prethalamic and descending corticothalamic axons form synapses. Supported analogous to classical synaptic transmission and argues against a paracrine by NSERC and CIHR mode of transmission (i.e. not volume transmission). To further address the manner by which DA signals in the midbrain, we have electrophysiologically recorded DA IPSCs while simultaneously measuring DA release with fast- 254 A229 scanning carbon-fiber voltammetry. By performing simultaneous CHRONIC DEPOLARIZATION UP-REGULATES measurements of DA signaling we have set out to determine the mechanisms MITOCHONDRIAL PROTEIN IMPORT IN DIFFERENTIATED by which DA is released somtodendritically. Briefly, we have found that, DA PC12 CELLS release in the midbrain is fast, vesicular, dependent upon calcium entry and Fong, Jamie1,3, Sirk, Dan, and Mills, LR 1,2,3. Department of Physiology1, not dependent upon reversal of the dopamine uptake transporter. These Faculty of Medicine2, University of Toronto, Division of Genetics and findings suggest that somatodendritic DA release occurs in a manner Development TWRI University Health Network3, Toronto analogous to rapid synaptic transmission.

The majority of mitochondrial proteins (>99%) are nuclear-encoded and must be imported into mitochondria. While deficits in import are known to 256 A231 impact virtually every aspect of mitochondrial function, little is known about SUBTHRESHOLD OSCILLATIONS OF MEMBRANE POTENTIAL how mitochondrial protein import is regulated in neurons. We hypothesized OF RAT SUBFORNICAL ORGAN NEURONS. that electrical activity, specifically chronic depolarization (50mm KCl), Mark Fry, Alastair V. Ferguson. Department of Physiology, Queen's regulates mitochondrial protein import in neurons. To assess the effects of University, Kingston KCl on import in differentiated PC12 cells we measured the import of 3 proteins; (a) mtGFP, an inducible GFP fusion protein targeted to Previous work has demonstrated that SFO neurons exhibit spontaneous mitochondria, (b) mtHSP70, a mitochondrial matrix chaperone, and (c) action potentials interspersed with periods of membrane potential oscillation Tom20, a key mitochondrial protein import receptor. Protein import to (MPO). We used whole cell patch clamp recording to investigate properties mitochondria, cytoplasmic levels of mitochondrial proteins and protein of thesoscillations. The amplitude, but not the frequency of the MPO expression were measured by Western blot of mitochondrial fractions, exhibited voltage dependence. The MPOs were not affected by application of cytoplasmic fractions and whole cell lysates respectively. mtGFP import in blockers f ionotrophic GABA and glutamate receptors, nor were they live cells and intramitochondrial turnover of mtGFP were assessed by flow affected by the application of Cd++ to block voltage gated Ca++ channels, or cytometry. Results: Exposure to KCl (50mM, iso-osmotic) significantly Cs+ to block HCN channels. The MPOs however were abolished by the increased mtGFP import; 24hrs post induction of mtGFP the fluorescence presence of TTX in the external recording solution, indicating a critical role signal increased by 33%+/-7 (n=5, p< 0.01) compared to controls and of voltage gated Na+ channels. Therefore, we investigated the properties of 40%+/-5 (n=5, p<0.001) by 48hrs. Western blots confirmed that KCl voltage gated Na+ channels using voltage clamp techniques. We found that increased mtGFP import; by 24hrs mtGFP increased by 59%+/-5 (n= 3, p< activation of the persistent Na+ current (INaP), but not the transient Na+ 0.05) compared to controls. mtGFP expression also increased significantly current (INaT) corresponded with the voltage dependence of activation of the but mtGFP intramitochondrial turnover was unchanged for up to 48hrs. The MPO. Moreover we found that voltage gated Na+ currents exhibited a KCl induced increase in mtGFP import was reversible, blocked by the L-type remarkably slow time dependent recovery from inactivation, which may play calcium channel antagonist, nimodipine, and further enhanced by treatment a role in determining the observed frequency of the MPO. with the L-type calcium channel agonist, BayK. The effects of KCl on import

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257 A232 application of ATP. Because it has been previously shown that channels LIGHT-DEPRIVATION DISRUPTS THE FUNCTIONAL AND whose Po does not change lack an associated kinase, the present data MORPHOLOGICAL PROPERTIES OF INHIBITORY A2 suggests that ATP, beyond its purpose as a phosphate donor, may directly AMACRINE CELLS OF THE RETINA shift the voltage required for half-maximal opening to more positive Alba Galán*, Ingrid K. Osswald, R. Anne McKinney & Derek Bowie. . Dept potentials. In addition, the right-shift in voltage-dependence by ATP on its Pharmacoly & Therapeutics, McGill University, Montreal own, may be masking any left-shift produced by PKC-dependent phosphorylation. This unexpected result prompted further investigation of Early sensory experience is crucial to the development and maturation of how nucleotides may interact with the cation channel. Preliminary synaptic circuits. In the retina, plastic changes in neuronal circuits have been experiments suggested that application of 0.1 mM GTP to the cytoplasmic mainly reported for excitatory ganglion cells. In this cell-type, light- face of channels in excised, inside-out patches increased the Po by left- deprivation (LD) interferes with normal dendritic modeling that in turn shifting the voltage-dependence and increasing the sensitivity. It remains to compromises visual processing. Importantly, Ca2+ influx through NMDA- be determined whether GTP is having an effect through an associated G- selective ionotropic glutamate receptors has been shown to be central to this protein or by acting directly on the channel. In general, long-lasting changes process. However, not all retinal cells express NMDARs. Recently we have in neuronal output and behaviour may be achieved by multiple factors identified a novel philanthotoxin (PhTX)-insensitive Ca2+-permeable converging on the voltage-sensor of an ion channel and altering its sensitivity AMPAR that is developmentally-regulated and selectively expressed in two to the membrane potential. inhibitory retinal cells, horizontal cells (HC) and A2 amacrine cells. Interestingly, neither cell-type expresses synaptic NMDARs suggesting that Ca2+-influx through PhTX-insensitive AMPARs during development may 259 B202 be also important in sculpting dendritic refinement. Here, we show that light ACTIVITY-DEPENDENT AND RECEPTOR-OPERATED CHANGES entering the eye shapes inhibitory synaptic circuit formation by triggering TO INTRACELLULAR CALCIUM IN NEUROENDOCRINE expression of a novel Ca2+-permeable AMPAR through a BDNF-dependent CELLS. mechanism. Specifically, we have addressed three questions;1) Does LD J.E. Geiger and N.S. Magoski. Department of Physiology, Queen's affect the composition of AMPARs? 2) Does LD affect the morphology of University, Kingston retinal cells? 3) Does BDNF trigger the expression of PhTX-insensitive AMPARs? Using cobalt (Co2+) staining and electrophysiological recordings Intracellular calcium dynamics are influenced by both extracellular to examine the expression of Ca2+-permeable AMPARs, we observed that calcium influx and calcium released from stores. Depending on the amount PhTX-insensitive receptors failed to express in dark-reared animals. In of initial calcium influx, a range of subsequent responses can result. We addition, the levels of expression of BDNF protein were completely examined intracellular calcium following receptor-operated or voltage-gated abolished in light-deprived rats. Interestingly, exogenous application of calcium influx in the bag cell neurons of the marine mollusc, Aplysia BDNF (3hrs, 250ng/ml) rescued PhTX-insensitivity in dark-reared rats. californica. Following a brief synaptic input, these neuroendocrine cells Finally, morphological analysis of A2 cells revealed that LD changed undergo a 30-minute period of repetitive firing, known as the afterdischarge. dendritic arborization of A2 cells. Moreover, presynaptic OFF-cone and rod- During this burst, a concomitant and rapid increase in intracellular calcium bipolar cells also showed disrupted morphology suggesting that PhTX- triggers the secretion of several neuropeptides to initiate egg-laying. insensitive Ca2+-permeable AMPARs may act as molecular guideposts for Cultured bag cell neurons were injected with the high-affinity calcium incoming axons. In summary, light entering the eye triggers expression of indicator, fura-PE3, and subjected to simultaneous ratiometric imaging and novel Ca2+-permeable AMPARs through a BDNF-dependent pathway that electrophysiology. Pharmacological activation of a non-selective cation may be critical in the development and sculpting of retinal inhibitory circuits. channel, previously implicated in driving the afterdischarge, produced both inward current and, as assessed by manganese-quench of fura fluorescence, calcium entry. This receptor-operated calcium influx pathway may 258 B201 contribute to plasticity or neuropeptide secretion during bursting. Voltage- NUCLEOTIDES DIRECTLY AND INDIRECTLY REGULATE gated calcium influx was investigated using trains of action potentials NEUROENDOCRINE CELL CATION CHANNEL VOLTAGE- delivered at 5 Hz, 10 sec (to mimic the synaptic input that initiates the DEPENDENCE afterdischarge) or 5 Hz, 1 min (to mimic the fast phase of the afterdischarge). K.E. Gardam and N.S. Magoski. Department of Physiology, Queen's While both trains transiently elevated intracellular calcium, only the 5 Hz, 1 University, Kingston min stimulus resulted in a calcium rise that markedly outlasted the initial influx, consistent with calcium-induced calcium release. Accordingly, Ion channel voltage-dependence is often modulated to change neuronal depletion of the smooth endoplasmic reticulum v store, with the calcium- output and trigger behaviour. In the bag cell neurons of Aplysia californica, ATPase blocker, cyclopiazonic acid, or collapse of the mitochondrial opening of a voltage-gated, non-selective cation channel drives a 30 minute hydrogen gradient, with the protonophore, FCCP, significantly attenuated the afterdischarge, that results in the secretion of egg-laying hormone and the elevation. Thus, robust levels of calcium influx are required to trigger initation of reproduction. It is known that protein kinase C (PKC) can closely calcium-induced calcium release in bag cell neurons; furthermore, both the associate with the channel, and thereby enhance both its activity and the endoplasmic reticulum and the mitochondria appear to sustain this release of excitability of the neuron; however, the mechanism of this modulation intracellular calcium. Activity-dependent induction of a prolonged calcium remains unknown. The current study used single-channel recording to elevation may be important in initiating secretion or in transcribing genes examine the effects of channel PKC-dependent phosphorylation on voltage- pertinent to reproduction. dependence. Application of 1 mM ATP to the cytoplasmic face of cation channel-containing excised, inside-out patches yielded either an increase or no change in open probability (Po), consistent with phosphorylation by associated PKC or no kinase association, respectively. Channels whose activity was upregulated by ATP (340% increase in Po) showed a slight left- ward shift in voltage-dependence, indicated by a change in V0.5 of -3 mV. Interestingly, channels whose Po did not change (-0.07% change in Po) showed a right-ward shift in voltage-dependence, with a change in V0.5 of +14 mV. No change in voltage-sensitivity or conductance was seen with the

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260 B203 262 B205 DETERMINING THE SPATIOTEMPORAL PATTERN OF DIFFERENTIAL ROLES OF CALCIUM BINDING PROTEINS IN SYNAPTIC INPUTS IN HIPPOCAMPAL NEURONS DURING MEMORY CONSOLIDATION IN LYMNAEA STAGNALIS POPULATION RHYTHMS Cong-hui Guo1, Guang-he Fei1, Ronald E. Van Kesteren2, and Zhong-ping *Jesse Gillis 1,2, Liang Zhang 1,3, Frances Skinner 1,2,3,4. 1 Division of Feng1. 1Department of Physiology, Faculty of Medicine, University of Fundamental Neurobiology, Toronto Western Research Institute, Toronto; 2 Toronto; 2Department of Molecular and Cellular Neurobiology, Vrije Department of Physiology, University of Toronto; 3 Department of Medicine Universiteit, Amsterdam, The Netherlands (Neurology), University of Toronto; 4 Institute of Biomaterials and Biomedical Engineering, University of Toronto Consolidation of aversive operant conditioning into long-term memory requires CREB dependent protein synthesis. However, molecular pathways In order to generate behaviourally significant activity in neurons, involved in CREB-mediated long-term memory consolidation remains to be synapses need to be assembled into specific patterns of connectivity. For investigated. Taking advantage of a well-established adverse operantly example, an inhibitory synapse can override excitatory synapses further from conditioned model of aerial respiratory behavior in the fresh water pond snail the soma along the same path, but has little effect on excitatory synapses Lymnaea stagnalis, we investigated the involvement of two calcium binding nearer to the soma. In this way, dendritic integration is a function of the proteins, neuronal calcium sensor-1 (NCS-1) and LCaBP (a novel Lymnaea specific morphology and biophysical properties of the neuron. Because these calcium binding protein) in formation of long-term memory (LTM). properties are very complex, it is a difficult problem to determine what Specifically, we found that upregulation of both total and phosphorylated pattern of inputs in a neuron produces physiologically realistic output. Using CREB1 coincided with elevations of NCS-1 and LCaBP in the snails with an in vitro preparation, signal processing methods, and a detailed reliable and consistent LTM formation 24 hours after operant training. To compartmental model of a CA1 hippocampal neuron, we developed methods explore the role of calcium binding proteins in memory consolidation, a to obtain constraints on the temporal profile of synaptic inputs necessary to dsRNA approach was used to trigger gene silencing of the calcium binding generate realistic output. Time-frequency analyses were used to determine proteins. Direct delivery of dsRNA specific to LCaBP, but not control characteristics of intact hippocampal preparation field and intracellular dsRNA, into the ganglia of the snail prior to the training, sufficiently reduced recocordings. The problem of spatial summation in field recordings was the specific gene/protein expression and prevented snails from learning and controlled for by determining a distinct pattern between variability in the memory consolidation; whereas a partial knockdown of NCS-1 did not affect temporal and spatial domain in this preparation. The time-frequency LTM. To further address the mechanism of LCaBP in LTM formation, we characteristics of the real hippocampal recordings are implemented in a screened the downstream targets of LCaBP and found that LCaBP detailed compartmental model of a CA1 hippocampal neuron using the knockdown decreased expression of CREB1, presynaptic exocytotic proteins genetic algorithm. This generated constraints on the pattern of synaptic input (syntaxin ) as well as endocytotic protein (dynamin), indicating that LCaBP to the model neuron. We found that excitatory input plays a greater role with plays a critical role in memory consolidation in Lymnaea stagnalis by greater distance from the soma in tuning neuronal output to physiologically regulating CREB expression. Taken together, our findings suggest that accurate temporal and frequency characteristics. Inhibitory input played a although both are upregulated, LCaBP, but not NCS-1, is essential for long- greater role in tuning output near to the soma. Because diseased brain states, term memory formation. and specifically epilepsy, are often strongly associated with a change in the signal measures (nonstationarity and time-frequency properties) we used, our method may allow us to make inferences as to the pattern of synaptic activity 263 B206 present in diseased vs functional brain states and the transition between the CHARACTERIZATION OF OLIGODENDROCYTE two. (This study was funded by CIHR, NSERC, and Epilepsy Canada.) MORPHOLOGICAL DEVELOPMENT AND MOTILITY IN HIPPOCAMPAL SLICE CULTURE USING SEMLIKI FOREST VIRUS AND MEMBRANE-TARGETED FLUORESCENT 261 B204 PROTEINS GLIAL CELL INDUCED NON-HOMEOSTATIC FAST SYNAPTIC M. Haber, S. Vautrin, K.K. Murai. Centre for Research in Neuroscience, SCALING Department of Neurology & Neurosurgery, Montreal General Hospital, Grant R.J. Gordon*, Dina Baimoukhametova and Jaideep S. Bains McGill University, Montreal

Current concepts of activity dependent changes in synaptic function rely Myelination is critical for the rapid propagation of action potentials in on our understanding of two disparate forms of plasticity: rapid, synapse most high caliber axons. Although the development of Schwann cells, the specific plasticity (LTP and LTD) and more recently, slower, compensatory myelinating cells of the peripheral nervous system, is well documented, scaling of all synaptic inputs in response to persistent changes in neuronal comparatively little is known about the three-dimensional maturation of activity (homeostatic plasticity). Whether a type of plasticity exists that oligodendrocytes, the myelinating cells of the central nervous system. Here, incorporates the rapid induction of LTP as well as the global scaling of we follow the developmental stages of oligodendrocytes in organotypic homeostatic plasticity remains to be established. In response to focal glial hippocampal slice cultures for 7-60 days using viral-mediated gene delivery cell stimulation by photolysis of caged MNI glutamate, we observe a long of membrane-associated fluorescent proteins. In culture, precursors lasting enhancement in the strength of glutamatergic synapses onto differentiate over time to form early premyelinating and later myelinating hypothalamic neurons. The induction of this plasticity occurs reliably within oligodendrocytes with identifiable nodes of Ranvier. Using confocal minutes like LTP; unlike LTP, however, the effect is not confined to specific microscopy and time-lapse imaging, we find that postmigratory NG2- synapses. Instead, changes are expressed globally at all glutamatergic positive cells have relatively low process density and are structurally stable. synapses contributing to spontaneous excitatory postsynaptic currents—a Later stage premyelinating cells, however, have increased process density, result similar to homeostatic plasticity. The augmentation of synaptic form dynamic growth-cone-like structures at their distal ends, and undergo strength requires the physical presence of glial processes around synaptic dramatic structural reorganization over the course of minutes. Later stage spaces and the activation of receptors for both glutamate and ATP. These myelinating oligodendrocytes, have pruned most of their processes and are data indicate that glial cells can induce a fast, non-homeostatic, global relatively stable. Our findings provide a detailed characterization of the enhancement of synaptic strength at excitatory inputs in the hypothalamus. morphology and motility of both premyelinating and myelinating oligodendrocytes and precursors as well as describe an in vitro system to study the process of myelination by oligodendrocytes positioned in a three- dimensional slice culture.

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264 B207 disorders such as psychostimulant addiction and schizophrenia, that are MICROGLIA PROCESSES BLOCK THE SPREAD OF DAMAGE IN known to be due to dysregulated dopamine and glutamate function in the THE BRAIN mesencephalon and mPFC. Support: Natural Sciences and Engineering Dustin J. Hines1, Sean J. Mulligan2, Brian A. MacVicar1. 1 University of Research Council of Canada. British Columbia, Brain Research Centre, Vancouver, British Columbia. University of Saskatchewan, College of Medicine 266 B209 Microglia cells, the immune cells of the brain, have recently been shown STRESS-INDUCED SPATIAL MEMORY DISRUPTION DEPENDS to rapidly extend processes to regions of nearby cellular damage. However ON LONG-TERM DEPRESSION IN THE HIPPOCAMPUS the impact of this response is unresolved. Using two photon laser scanning *J. G. Howland1, T. Wong1, C. J. Fox2, Y. Ge1, K. I. Russell2, K. Brebner1, microscopy we show that microglia process extension is an important A. G. Phillips1, J. Weinberg3, B. R. Christie2, Y. Wang1. 1Dept Medicine and protective response that prevents the spread of damage into surrounding the Brain Research Centre, Univ British Columbia, Vancouver, 2Dept undamaged tissue. Focal lesions were made in hippocampal slices and Psychology and the Brain Research Centre, University of British Columbia, ensuing process outgrowth of activated microglia was monitored with time- Vancouver, 3Depts Cellular and Physiological Sciences and Psychology and lapse microscopy. We found that inhibiting microglia Cl- channels blocked the Brain Research Centre, University of British Columbia, Vancouver the rapid outgrowth of processes in response to the lesion. Lesion volume was measured and found to decrease in control conditions where microglia Stress is often detrimental to cognitive function. For example, acute processes reached and contained the lesion. In contrast, when microglia stress impairs memory retrieval in rodents. Additionally, exposure to stress processes outgrowth was blocked by either inhibiting microglia Cl- channels alters the expression of synaptic plasticity in the hippocampal CA1 region by or by selectively ablating microglia, lesion volume increased and damage favoring long-term depression (LTD) over long-term potentiation. However, spread into surrounding tissue disrupting dendrite morphology. These data it is unknown if altered synaptic plasticity causes the impairment in memory show that microglia processes are resistant to the excitotoxic effects of after stress. The present experiments used three strategies to test this factors released by damage and in fact microglia grow into regions of brain hypothesis. Current theories suggest that LTD induction in hippocampal damage in order to protect surviving neurons. When microglia processes slices depends on NR2B-containing NMDA receptors. As a result, we arrive at the lesion and engulf the damage region they act to contain the pretreated rats with the NR2B-specific antagonist Ro25-6981 (i.p., 6 mg/kg), harmful factors released by the damage. which blocks LTD induction following acute stress in vivo, and successfully Glutamate is an excitotoxic factor that is released at sites of CNS damage reversed a stress-induced memory deficit in a standard water maze task. To and the GLT-1 glutamate transporter that is expressed in microglia may help confirm that the effect of Ro25-6981 was due to LTD inhibition, we also to prevent the spread of damage. Therefore, the question of whether blocked the expression of LTD by disrupting the regulated endocytosis of microglia are harmful or helpful in the brain appears to have a partial answer postsynaptic AMPA receptors with a GluR2 subunit derived interference in the fact that these cells perform a highly organized and critical role in the peptide. Pretreatment of rats with the interference peptide also abolished the rapid containment of damage. stress-induced memory impairment. Recent evidence suggests that stress may reduce glutamate transport, thereby allowing activation of NR2B- containing receptors predominantly located extra-synaptically in adult rats. 265 B208 To determine if induction of hippocampal LTD could mimic the effects of DOPAMINERGIC MODULATION OF GLUTAMATERGIC-BASED stress, we bilaterally infused the glutamate transporter inhibitor DL- threo- LONG-TERM POTENTIATION IN THE PREFRONTAL CORTEX, beta-benzyloxyaspartate (TBOA) into the hippocampus and found that like IN VIVO acute stress treatment, TBOA treatment enabled LTD and impaired memory Romina D. Coppa-Hopman* and Ronald J. Racine. McMaster University - retrieval. Most importantly, both the LTD and memory impairments were Department of Psychology, Neuroscience, and Behaviour reversed with Ro25-6981. Together, these experiments support the notion that activation of NR2B-containing NMDA receptors and subsequent LTD Drug addiction and behavioural sensitization are associated with a induction causes memory impairment following acute stress. reorganization of mesolimbocortical circuitry, which we have attempted to model with glutamatergic-based long-term potentiation (LTP) and long-term depression (LTD) in the mesencephalon and medial prefrontal cortex 267 B210 (mPFC). The objective of the following experiments was to examine the CHRONIC NERVE GROWTH FACTOR TREATMENT INCREASES effects of dopamine-2 (D2) receptor family specific agonists and antagonists ACETYLCHOLINE AND GLUTAMATE RELEASE FROM on glutamatergic-based LTP in the mPFC in the chronic in vivo preparation CHOLINERGIC NEURONS OF THE RAT MEDIAL SEPTUM / using fully-awake, freely-moving rats. Male Long-Evans rats were DIAGONAL BAND OF BROCA surgically implanted with stimulating electrodes into the corpus callosum and Carey Y.L. Huh§*, Marc Danik§, Louis-Eric Trudeau+, and Sylvain recording electrodes into the mPFC. Subjects were systemically Williams§. § Douglas Hospital Research Centre & McGill University, administered drug together with high frequency stimulation for the induction Montreal, + Department of Pharmacology, Faculty of Medicine, Université of LTP. The D2 receptor antagonist sulpiride (3mg/kg/ml, 6mg/kg/ml, de Montréal, Montreal 12mg/kg/ml) significantly decreased LTP, compared to the control group, in a dose-dependent fashion. The D2 receptor agonist quinpirole hydrochloride Nerve growth factor (NGF) is a neurotrophic factor important for the (0.025mg/kg/ml, 0.25mg/kg/ml, 0.5mg/kg/ml) significantly increased LTP in survival, growth and function of cholinergic basal forebrain neurons. a dose-dependent fashion. The D2 receptor agonist also induced behavioural However, little is known about the function of NGF on other basal forebrain sensitization. The intensity and frequency of behavioural sensitization was neurons such as glutamatergic or GABAergic neurons. Here, we used positively correlated with the LTP effect, with an increased expression of neurons from the rat medial septum/diagonal band of Broca (MS-DBB) to sensitization in the LTP groups. These results demonstrate that test whether chronic NGF treatment affects the synaptic function of glutamatergic-based LTP in the mPFC and behavioural sensitization are cholinergic, glutamatergic and GABAergic basal forebrain neurons. We positively modulated by D2 receptors in the chronic in vivo preparation. As isolated single rat MS-DBB neurons in culture, allowing them to establish the D2 receptor-rich neurons are located largely in mesencephalic nuclei that, synaptic contacts onto themselves. One group of neurons chronically in turn, project to the mPFC, the D2 effects may be indirect. This plasticity received NGF (25ng/ml) while another group received none. After 2-4 weeks modulation needs to be more deeply explored to determine its relationship to in culture, we used whole-cell electrophysiology to measure the amplitude of

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evoked autaptic EPSCs or IPSCs. Cholinergic MS-DBB neurons were 269 B212 identified using 192IgG-Cy3, a fluorescent p75NTR receptor antibody. MEDIAN RAPHE STIMULATION RESETS HIPPOCAMPAL Neurotransmitters involved in postsynaptic currents were characterized THETA ACTIVITY AND RELATED CELLULAR ACTIVITY pharmacologically. In some experiments, a trk inhibitor K252a was added Jesse Jackson* and Brian H. Bland. University of Calgary, Behavioral with NGF to study the role of trkA-mediated signaling. To investigate the Neuroscience Research Group synaptic mechanisms underlying changes in evoked EPSCs, miniature EPSCs were recorded. We found that chronic NGF treatment led to a 37-fold Hippocampal theta rhythm is thought to be under inhibitory control of the increase in the amplitude of cholinergic EPSCs and a 22-fold increase in the median raphe nucleus (MRn). High frequency electrical stimulation of the amplitude of glutamatergic EPSCs in “cholinergic” MS-DBB neurons MRn elicits a desynchronization of hippocampal theta rhythm while MRn releasing both neurotransmitters. However, NGF did not affect autaptic lesions produce the release of theta rhythm. Despite a detailed analysis of currents in neurons releasing glutamate or GABA only. K252a prevented the MRn stimulation on hippocampal field activity (Vertes et al., 2005), no NGF-induced increase in glutamatergic EPSCs but not cholinergic EPSCs. systematic study of hippocampal theta-related cellular activity has been Furthermore, chronic NGF treatment led to a 2-fold increase in the frequency performed. In this experiment we stimulated the MRn at 0.5Hz and generated of miniature EPSCs in cholinergic neurons but did not affect the amplitude perievent time histograms (PETH) for ongoing EEG and single units of the events. The present study demonstrates, for the first time, that chronic recorded from the dorsal hippocampus in urethane anesthetized rats as the NGF treatment dramatically increases both glutamate and ACh release from animals cycled between theta and non-theta states. Stimulation produced a cholinergic MS-DBB neurons. TrkA-mediated signaling was found to be reset of hippocampal theta field, without producing a change in power or responsible for the NGF-induced increase in glutamate release but not for the frequency of the field activity. Single units were inhibited with a latency of 5 increase in ACh release. The present study illustrates that NGF is crucial not ms and duration of 68 ms before returning to baseline firing rates. In only for cholinergic function but also for glutamatergic function in the septo- addition, a subset of phasic theta-on cells (n=14) responded with an hippocampal pathway, which plays an important role in memory. oscillatory PETH whereas 9 cells did not exhibit an oscillatory response. Post-hoc analysis of spiking parameters (phase relation to theta, interspike interval, firing rate, strength of phase relation) during spontaneous theta 268 B211 identified the non-oscillatory responding cells as a unique group of rhythmic LOCALIZING CRITICAL NEURONAL CIRCUITRY BY RANDOM cells that differed from oscillatory responding cells according to the above GENETIC SILENCING OF INTERNEURONS IN INTACT parameters. Despite maintaining different phase relations to spontaneous DROSOPHILA LARVAE hippocampal theta, all phasic theta-on cells were reset to a common phase Balaji G. Iyengar*1, C. Jennifer Chou2, Katrina M.Vandamme1, Xiaoli following MRn pulse. All rhythmic responses were state dependent, in that Zhao3, Ana R. Campos3 and Harold L. Atwood1.. 1 Department of they occurred when the pulse was administered during theta, but not non- Physiology, University of Toronto. 2 School of Medicine, Queen’s University, theta states. Interestingly, phasic theta-off cells were also reset to the same Kingston. 3 Department of Biology, McMaster University, Hamilton phase as phasic theta-on cells following the MRn pulse. Tonic theta-on cells were not consistently altered by stimulation, while cells unrelated to the We have investigated how stereotypic locomotion and sensory-motor hippocampal field activity were not affected. These results suggest high behaviours in the Drosophila larva are encoded. Towards this goal, we frequency stimulation of the MRn acts to desynchronize hippocampal EEG employed the UAS/Gal4 and MARCM methods to express green fluorescent by resetting all rhythmic hippocampal activity on a short time scale. protein (GFP) and a temperature-sensitive mutant allele of the vesicle- Additionally, these data demonstrates a cell specific site of action for the recycling protein Dynamin (called shibire(ts1) or shi(ts1) in Drosophila) in MRn modulation of hippocampal theta which is dependent on brainstate. various subsets of neurons. It is well known that shi(ts1) mutant larvae Funding support: NSERC Grant number A9935 to BHB and NSERC CGS to exhibit rapid paralysis at non-permissive temperature (29 ºC) due to JJ. disruption of endocytosis, which in turn results in synaptic vesicle depletion. It has also been demonstrated previously that overexpression of shi(ts1) in a global manner in the larval CNS results in rapid paralysis. Here, we first 270 B213 describe behavioral and kinematic analyses to study shi(ts1) mediated FUNCTIONAL COUPLING BETWEEN NMDA RECEPTORS AND dissection of larval neuronal networks. By constructing transgenic strains TRPM2 CHANNELS IN HIPPOCAMPAL NEURONS that overexpress lower or higher levels of shi(ts1) in different parts of the Michael F. Jackson, Michelle E. Olah, John F. MacDonald. University of larval nervous system, we demonstrate that an optimal level of transgenic Toronto, Department Physiology, Toronto shi(ts1) expression is important for temperature-mediated disruption of larval locomotion and a simple sensory-motor response. Next, we used the TRPM2 is a Ca2+-permeable, non-selective cation channel that is gated transgenic shi(ts1) strain to create a functional-MARCM (f-MARCM) by ADP-ribose (ADPR). During oxidative stress, mitochondria generate free system for examining the role of randomly selected candidate cholinergic ADPR, which is released into the cytoplasm where it activates TRPM2. This neurons in the initiation and maintenance of locomotion and the touch- results in Ca2+ dysregulation and subsequent cell death. Since oxidative mediated avoidance response. In our f-MARCM system, random subsets of stress, generated in neurons as a consequence of the excitotoxic stimulation interneurons and/or sensory neurons are permitted to express UAS/Gal4 of NMDA receptor (NMDARs), contributes to delayed Ca2+ overload and mediated GFP and shi(ts1) due to the homologous recombination of Gal80 neuronal demise, we hypothesized that TRPM2 may be activated repressor transgene that occurs in some precursors during embryonic downstream of NMDARs. We first employed RT-PCR and Western blotting development of the nervous system. We tested such mosaic larvae for to identify TRPM2 in cultured hippocampal neurons. Immunostaining temperature-dependent motor defects or normal behaviors and then mapped demonstrated diffuse, extrasynaptic expression of TRPM2, as TRPM2 failed the projection patterns of labeled neurons. Due to the excellent GFP to colocalize with the synaptic marker PSD-95. Whole-cell patch-clamp expression level, the brain compartments innervated by labeled interneurons recordings were subsequently carried out to investigate the presence of could be accurately mapped and their Dynamin expression levels could also functional TRPM2 channels in these cells. Inclusion of 0.3 mM ADPR in the be visualized. The f-MARCM strategy constitutes an unbiased screen for patch pipette induced a large (-558.5 ± 81.9 pA) inward current (IADPR) in identifying functionally important interneurons. Our results indicate that a cultured hippocampal neurons that was inhibited upon removal of limited subset of candidate cholinergic interneurons are necessary for the extracellular Ca2+, a hallmark characteristic of TRPM2-mediated currents. proper execution of larval locomotion and sensory-motor behaviours. Furthermore, the resulting current could be blocked by clotrimazole (10 µM), flufenamic acid (100 μM) and ACA (20 μM) but was insensitive to La3+ (0.1 mM), consistent with TRPM2 activation. Interestingly, IADPR was facilitated by the activation of NMDARs, an effect not simply attributed

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to elevated intracellular Ca2+ and suggestive of a more intimate coupling 272 B215 between NMDARs and TRPM2. We next investigated whether a TRPM2- DYNAMICS OF SYNCHRONIZATION IN AN INHIBITORY like conductance (ITRPM2-like) could be activated downstream of NMDAR NETWORK OF NEURONAL OSCILLATORS activation. Repeated (1/60 s for 15 min) applications of NMDA (100 µM, 5 Kane A 1, Skinner FK 2,3,1,4 and Dostrovsky JO 1. 1 Dept. of Physiology, s) to hippocampal neurons caused the progressive activation of a sustained University of Toronto, Toronto. 2 Dept. of Medicine (Neurology), University inward current (-537.3 ± 68.8 pA). As with IADPR, ITRPM2-like was of Toronto, Toronto. 3 Toronto Western Research Institute, University Health abolished by the removal of extracellular Ca2+, could be blocked by Network, Toronto. 4 Institute of Biomaterials and Biomedical Engineering, clotrimazole and was insensitive to La3+. The extrasynaptic localization of University of Toronto TRPM2 suggested that these channels may be preferentially coupled to extrasynaptic NR2B containing NMDARs. This was confirmed in There is increasing evidence that brain rhythms play a fundamental role experiments demonstrating that Ro 25-6981 (0.5 μM), a NR2B in the execution and regulation of cognitive and behavioral functions. Recent selective antagonist, prevents the development of ITRPM2-like by repeated studies also highlight the importance of inhibitory subnetworks in rhythm NMDA applications. Taken together, these results suggest that hippocampal generation. This has motivated the development of many experimental and neurons possess functional TRPM2 channels whose activation lies computational models which reveal their ability to support a rich structure of downstream of NMDARs. activity patterns such as synchronous activity, clustering, and waves. However, there are very few analytical characterizations of such patterns. Here, we consider a biophysical model describing a network of hippocampal 271 B214 basket cells (X. J. Wang and G. Buzsáki, J. Neurosci. 16:6402, 1996) and MITOCHONDRIAL REMODELLING IN DIFFERENTIATED PC12 attempt to determine conditions under which certain specific modes of CELLS activity can be observed. We use the fast/slow structure of the equations Patrick Kaifosh, Alexandra Haagaard, LR mills. TWRI, Genetics and involved to derive a simpler neuronal model that captures the essential Development Division, UHN Department of Physiology University of features of the Wang-Buzsáki model interneuron and allows an analytical Toronto treatment. We then consider a pair of such neurons coupled through GABA- A type synapses and describe how the synaptic time scales interact with the Mitochondrial morphology can fairly be described as dynamic, since intrinsic dynamics to generate various stable configurations (in-phase and out mitochondria are capable of markedly changing shape within minutes under of phase synchrony, suppression) depending on initial conditions and basal conditions. Dramatic permanent morphological changes in entire parameters. We also discuss the implications of this analysis for larger mitochondrial populations within a cell have also been associated with networks. This new approach gives a more precise characterization of the disease states and acute cell injury. Little is known about how changes in network dynamics and provides new insights into the synchronization of morphology alter mitochondrial function or to what extent changes in shape inhibitory neurons. These findings may also provide new insights into are reversible. Hypothesis: Mitochondrial morphology is inherently plastic; possible mechanisms of oscillatory activity in the basal ganglia which specifically, mitochondria are capable of rapidly changing morphology in contain large numbers of GABAergic neurons and interconnections. response to osmotic perturbations that cause cell swelling and shrinking. We Supported by CIHR FRN 42505. used confocal microscopy to monitor mitochondrial dynamics in live differentiated PC12 cells stably transfected with an inducible, mitochondrially targeted, GFP fusion protein (mtGFP). In cells at rest, 273 B216 mitochondria throughout the cell displayed a characteristic elongated D1 AND D2 DOPAMINE RECEPTORS INTERACT DIRECTLY morphology. Individual mitochondria moved in and out of the focal plane WITH N-TYPE CALCIUM CHANNELS AND DIFFERENTIALLY over the course of minutes, and, over the course of 10s of minutes, changed REGULATE CHANNEL ACTIVITY AND SURFACE EXPRESSION shape. In neurons where normal media was replaced by water or diluted A.E. Kisilevsky1, S. Mulligan2, B.A. MacVicar3 & G.W. Zamponi1. media, mitochondrial morphology changed markedly; within 60s 1Hotchkiss Brain Institute, Department of Physiology and Biophysics, mitochondria rounded up and became spherical. These changes in Faculty of Medicine, University of Calgary; 2 Department of Physiology, morphology were rapidly reversible; upon replacement of the hypotonic University of Saskatchewan, Saskatoon; 3 Brain Research Center, University media with norm-osmotic media, mitochondria reverted to elongated forms of British Columbia, Vancouver within 2min. Similar results were obtained when this process was repeated for up to 4 cycles of swelling and shrinking. Multiple cycles of N-type calcium channels are located on dendrites and at pre-synaptic ‘mitochondrial remodeling’ did not alter cell viability 1, 5, 24 or 48 hrs later nerve terminals where they play a fundamental role in neurotransmitter (e.g. at 24 hrs, cell viability was 89±5% versus 91±3% in control cultures). release. They are potently regulated by the activation of a number of Western blot showed negligible release of cytochrome-c at 1 hr or 24 hrs. different types of G protein coupled receptors (GPCRs), which results in Experiments on mtGFP minus cells using each of Rhod-123 and Mitotracker inhibition of channel activity. It is well established that certain PTX- Green FM to label mitochondria confirmed the mtGFP results, although sensitive Gαi/o coupled receptors, such as dopamine D2 receptors, Rhod-123 and especially Mitotracker showed significant bleaching. Cell mediate this type of inhibition of N-type channel activity. However, the swelling caused a small decrease in mitochondrial membrane potential. Our coupling of D1 receptors to these channels remains poorly characterized. results demonstrate that neuronal mitochondria have the potential to remodel Using heterologous expression in HEK 293T cells, we show via whole cell in response to osmotic perturbations and that this ‘mitochondrial remodeling’ patch clamp recordings that both D1 and D2 receptors mediate G protein is rapid, reversible, and repeatable. Further, this remodeling is not associated dependent inhibition of channel activity. This data demonstrates that, similar with decreased neuronal viability or cytochrome c release. Ongoing studies to the D2 receptor, D1 receptor activation allows the channel to be effectively are examining the role of the membrane cytoskeleton in this mitochondrial regulated by liberated Gβγ subunits. Yet, greater inhibition is remodeling, specifically the role of actin and spectrin. observed with D2 receptors suggesting that these receptors may be more effectively coupled to the channel. Co-immunoprecipitation, pull-down assays, and confocal microscopy reveal that both D1 and D2 receptors are physically associated with N-type channels, suggesting the existence of DA receptor-N-type channel signalling complexes. These interactions were found to be mediated by distinct structural moieties on both receptor and channel. Hence, the unique physical association between channels and

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receptors might serve as a key modulator of coupling efficacy. Cell surface three LVA Ca2+ channel isoforms (Cav3.1, Cav3.2, Cav3.3) with distinct immunoluminometry reveals that both receptor subtypes influence channel kinetics have been identified in the ventrobasal complex (VB) and trafficking of the channel to and from the plasma membrane, to differential thalamic RE nucleus. Previous electrophysiological and modelling studies degrees. These data provide further support for stable receptor- channel suggested that kinetically different IT channels might be expressed in a signalling complexes which allow for indirect regulation of channel activity compartmentalised manner in TC and RE cells. Therefore, the knowledge of via alteration of the degree of channel surface expression. Finally, two- their detailed cell-surface distribution is essential for understanding the LVA photon laser scanning microscopy provides evidence that activation of D1 responses in thalamic neurons. In order to disclose the somato-dendritc receptors robustly inhibits N-type channel activity in pyramidal neurons of density of IT channels in VB and RE nuclei of the cat, we utilised the high- rat pre-frontal cortex. Given the fundamental nature of calcium influx resolution immunolocalization technique combined with electron through N-type channels in synaptic release, these data help to further our microscopy. Cav3.1 channel isoform was mainly expressed in the VB, while understanding of how neurotransmission is modulated. Furthermore, they strongly Cav3.3-immunopositive cells were predominantly found in RE provide insight into the mechanisms by which intracellular calcium nucleus. Immunogold particles were predominantly distributed on somatic concentrations may be fine-tuned, during dopaminergic signalling, in both and dendritic plasma membranes, although immunosignal was also present in cultured cells and neurons. the cytoplasmic membrane delineated structures. In the VB thalamus, most of the neurons were strongly immunopositive for Cav3.1 subunit and less immunopositive for Cav3.3 with a labelling localised mainly in the somatic 274 B217 and the proximal dendritic plasma membrane. In RE cells, distribution of ROLE OF NERVE TERMINAL CALCIUM IN TEMPERATURE- Cav3.1 was mainly restricted to cell bodies and proximal dendrites similar to INDUCED FAILURE OF SYNAPTIC TRANSMISSION the expression pattern of relay cells. In contrast, Cav3.3 channels were Klose M.K., Robertson R.M., and Atwood H.L.. Department of Physiology, distributed over extended length of the dendritic arbour. These results suggest University of Toronto that Cav3.1 and Cav3.3 channel isoforms may contribute to LVA calcium- dependent responses mainly at somatic and proximal dendritic level in VB Failure to transmit a signal across the Drosophila neuromuscular junction and RE nuclei, although mediation of Ca2+ influx in the distal dendritic occurs at elevated temperatures in concert with an elevation in resting regions of RE neurons could be controlled mainly by Cav3.3 channels. calcium concentration above 200nM. Above this 200nM threshold the ability Supported by NSERC and CIHR. to stimulate a calcium response in boutons is lost suggesting either a loss of action potential propagation or a disruption of calcium channel activation. Electrotonic stimulation, which bypasses sodium channels and directly 276 B219 activates calcium channels, cannot fully rescue stimulus-induced calcium C6 GLIOMA CELLS AS TARGETS IN RECOGNITION EVENTS OF responses and does so only briefly; synaptic transmission also recovers with NATURAL KILLER (NK) CYTOTOXICITY a diminished amplitude for only a brief period of time. This suggests that Kovaru F.(1,2), Kovaru H. (3), Zelnickova P. (1), Fiserova A.(4), Dvorak hyperthermia-induced failure of synaptic transmission may result from R.(1), Havrdova E. (3). (1) University of Veterinary and Pharmaceutical calcium channel inactivation. Nerve terminals treated to a prior heat shock Sciences, Brno, (2) Institute of Animal Physiology and Genetics, Acad.Sci., or those expressing Hsp70 were better able to maintain near-normal resting Brno, (3) 1st Faculty of Medicine, Charles University, Prague, (4) Institute calcium concentrations and synaptic transmission at higher temperatures. of Microbiology, Acad.Sci., Prague, Czech Rep Calcium influx and calcium clearance were also protected by prior heat shock. Thus, Hsp70 sustains mechanisms of calcium entry and intracellular Defence mechanisms as natural killer (NK) cytotoxic activity are key regulation. Conversely, disruption of mechanisms clearing calcium at high events in immune surveillance. In contrast to this general knoledge, prenatal temperatures, the endoplasmic reticulum Ca+2-ATPase with thapsigargin and neonatal pig NK activity was not measurable with usual K562 and the plasma membrane Ca+2-ATPase with high pH, significantly erythroleukemia cell targets in comparison with high levels of adult NK accelerated the temperature-induced rise in resting calcium concentration and cytotoxicity. Aim was to analyse pig fetal and early postnatal NK cytotoxicity decreased the temperature at which evoked calcium responses failed. with other targets .- original C6 glioma cells (ATCC CLM 107, Interestingly, disruption of the sodium/calcium exchanger by reducing Rockville,MD) and our modified rat C6 glioma cells transfected (t) pig Na+ in the physiological solution disrupted evoked Ca+2 responses without lymphocyte markers (MHC Class II, CD2, etc) checked by FACS analysis. a significant rise in [Ca+2]r. This suggests a role for the Na+/Ca+2 exchanger Marked NK activity was demonstrated on feta pig day 100, with increasing in mediating hyperthemia-induced rise in [Ca+2]r. The data also suggest that levels on neonatal and postnatal day 35 in blood mononuclear cells or spleen disruption of evoked calcium responses does not require elevated [Ca+2]r lymphocytes with (t)C6 glioma cells targets by 51 Cr-release or non-isotope and can result from the misregulation of other ions. In general, elevated method. On the other backgound levels were measured using K562- or resting calcium concentration was linked synaptic transmission failure at original C6 glioma cells at mentioned age intervals, these targets were more high temperatures. Conversely, more stable resting calcium concentration effective in later postnatal period.. Thus use of modified (t) C6 glioma cells sustained evoked calcium responses and synaptic transmission. Thus, the with combination of xenogeneic and syngeneic cell surface determinants can thermal limit of synaptic transmission may be directly linked to the stability contribute to better recognition by NK cells not fully maturated in fetal/ of ion regulation. (This study was funded by the Canadian Institutes for neonatal period. Supported by grants MSM 0021620849, GACR Health Research) 524/05/0267, MSM 6215712403 and IAA 500 2006 20.

275 B218 277 B220 SUBCELLULAR DISTRIBUTION OF LOW-VOLTAGE ACTIVATED Aβ-INDUCED TRUNCATION OF SYNAPTIC PROTEIN T-TYPE CA2+ CHANNEL SUBUNITS (CAV3.1 AND CAV3.3) ON DPYSL3 IN PRIMARY CORTICAL NEURONS RETICULAR AND THALAMOCORTICAL NEURONS IN THE CAT Renata Kowara, Leslie Brown, Michel Menard and Balu Chakravarthy. Krisztina Kovács*, Attila Sík, Igor Timofeev. Centre de Recherche Universite Institute for Biological Sciences, National Research Council, Ottawa Laval Robert-Giffard, Quebec Using a proteomics approach, we were able to detect a number of protein Low-voltage activated (LVA) T-type calcium channels (IT) are implicated expression changes in primary cortical neurons exposed to Aβ 1-42. in the pacemaker activities of thalamocortical (TC) and GABAergic reticular One such protein whose expression is strongly reduced after Aβ (RE) cells and have a pivotal role in the thalamic sleep oscillations. Recently, application is dihydropyrimidinase-like 3 protein (DPYSL3). This synaptic

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protein plays a key role in cytoskeleton organization, neuronal et al, 2001 J. Neurosci). S6 and other ribosomal mRNAs are regulated differentiation, axonal outgrowth and neuronal regeneration. We have through a TOP (5’ terminal oligopyrimidine tract) sequence that normally previously shown that glutamate excitotoxicity and oxidative stress result in represses translation. This repression is relieved by TOP through a pathway calpain-dependent cleavage of DPYSL3 (Kowara et al., J. Neurochem, 2005) independent of other TOR targets such as S6 kinase and 4EBP. In order to and that it involves nitric oxide synthase (Kowara et al. Brain Res, 2006) and investigate the role of TOP mRNAs in Aplysia neurons, pleural-pedal ganglia phospholipase A2 signaling. We now show that this Aβ-induced were subjected to 10 min serotonin (5-HT) treatment, lysed and polysome decrease in DPYSL3 levels is, in fact, due to a calpain-dependent truncation profiles were generated on sucrose gradients, and were consequently and involves the activation of the NMDA receptor, because its truncation can analyzed by quantitative real-time PCR. In control ganglia S6 and eEF2 be blocked by both calpain inhibitors and the NMDA receptor antagonist, (TOP-containing mRNAs) were enriched in sub-polysomal fractions MK-801. The presence of these inhibitors also reduces Aβ-induced compared to other transcripts (Rab-3a and actin). This result suggests that neuritic damage and improves cell viability. TOP mRNAs are translationally repressed at rest. After 5-HT treatment, a sizeable proportion of S6 mRNA was found in the polysome fraction, indicating removal of TOP repression. Surprisingly, eEF2 mRNA was still 278 B221 repressed. These results are consistent with the increase in translation of a AN INCREASE IN THE FREQUENCY OF QUANTAL EVENTS subset of TOP mRNAs after 5-HT addition. Further work will examine the ACCOMPANIES THE INDUCTION OF CHEMICAL LTD AT dependence of this on TOR activation and the generality with which this can HYPOTHALAMIC GLUTAMATE SYNAPSES be extended to other TOP mRNAs. J. Brent Kuzmiski, Jaspreet Khangura, Quentin J. Pittman and Jaideep S. Bains. Hotchkiss Brain Institute, University of Calgary 280 B223 In response to numerous physiological challenges including dehydration, RELATIONSHIPS BETWEEN SUBSTANCE P, NK1 RECEPTORS stress, lactation, and parturition, noradrenaline (NA) is released in the AND SEROTONIN NEURONS IN THE DORSAL RAPHE NUCLEUS paraventricular nucleus (PVN) of the hypothalamus to modulate OF ADULT RAT neuroendocrine output. In this study, using whole-cell patch clamp B. Lacoste *, M. Riad, L. Descarries.. Departments of Pathology and Cell recordings from both parvocellular and magnocellular neuroendocrine cells Biology and of Physiology, GRSNC, Faculty of Medicine, Université de in the PVN, we show that bath application of NA (3-5 min, 100 – 200 uM) Montréal, Montreal induces a robust, fast-acting, permanent chemical LTD at glutamatergic synapses. Induction of this chemical LTD is activity dependent because LTD In addition to its neurotransmitter/modulator role in pain perception, was only observed at synapses that were repetitively stimulated during NA substance P (SP) is involved in a regulation of mood, and the blockade of its application. Alternatively, when EPSCs were not evoked in synapses for 5 neurokinin-1 receptor (NK1r) has been shown to have antidepressant-like minutes during NA application, the EPSC amplitudes were not different from effects in human. In rodents, treatment with NK1r antagonists and induces a control initially; however, subsequent stimulation of these synapses in the desensitization of 5-HT1A autoreceptors and increases the firing of serotonin presence of NA resulted in the rapid induction of LTD. The paired pulse ratio (5 HT) neurons in the dorsal raphe nucleus (DRN). In a recent, double of evoked EPSCs was increased following induction of LTD suggesting that labeling, immuno-electron microscopic study, we have demonstrated the it occurred at a presynaptic location. Interestingly, chemical LTD was existence of NK1r in a subpopulation of DRN 5 HT (TpOH-positive) accompanied by a robust increase in the frequency of quantal glutamatergic neurons mostly located in the caudal half of the nucleus (Lacoste et al., events that was reversible upon wash of NA. To determine if these opposing 2006). Interestingly, in these soma-dendrites, the NK1r was always found actions of NA on the probability of spontaneous release versus evoked mainly in the cytoplasm, whereas it predominated on the plasma membrane release occur at the same synapses we recorded NMDA-dependent mEPSCs of TpOH-negative dendrites. Here, we combined SP and NK1r in 0 Mg2+ ACSF. Application of MK801 completely blocked spontaneous immunolabeling in the caudal half of the DRN to examine the relationships NMDA-EPSCs and prevented the subsequent activation of evoked NMDA between SP axon terminals and dendritic profiles endowed with cytoplasmic currents, suggesting that spontaneous and evoked glutamate release occurs at (5-HT neurons) versus plasma membrane (non 5-HT neurons) NK1r. In the same synapses. By facilitating spontaneous glutamate release while singly SP (DAB)-labeled material (n=3), the frequency with which SP- depressing evoked transmission, NA places a premium on local forms of labeled profiles displayed a junctional complex in single thin sections (18%) intranuclear signaling while isolating PVN neurons from changes in activity indicated that many of these terminals (~ 50%) are synaptic. In doubly SP in afferent nuclei. (DAB)- and NK1 (gold)-labeled material (n=3), SP terminals were frequently found in direct contact with or in the immediate vicinity of dendritic profiles endowed with cytoplasmic NK1r. This was never seen in the case of 279 B222 dendrites bearing membranous NK1r. These preliminary observations are CHARACTERIZATION OF TOP TRANSLATION IN APLYSIA consistent with the hypothesis of a tonic activation and internalization by SP NEURONS of NK1r in DRN 5 HT neurons. (Supported by CIHR grant MOP 3544). Margaret Labban, Wayne Sossin. Montreal Neurological Institue, McGill University 281 B224 The sensory-motor reflex of the marine mollusk Aplysia is a good model SELECTIVE ABLATION OF PROLIFERATING MICROGLIAL for understanding the changes in behavior linked to synaptic modifications. CELLS EXACERBATES ISCHEMIC INJURY IN THE BRAIN Behavioral sensitization in Aplysia is mediated partially by an increase in Lalancette-Hébert, M., Gowing, G., Simard, A., Weng, YC. and Kriz, J.. synaptic strength between sensory and motor neurons called long-term Department of Anatomy and Physiology, Laval University, Centre de facilitation (LTF). Translational regulatory systems are important for many Recherche du Centre Hospitalier de l'Universite Laval, Quebec aspects of LTF. In particular activation of the target of rapamycin (TOR) signalling pathway is activated by LTF and is important for local and somatic Here we report in vivo evidence of a neuroprotective role of proliferating regulation of translation. However, the important downstream targets of TOR microglial cells in cerebral ischemia. Using transgenic mice expressing a have not yet been determined in this system. One possibility of a TOR target mutant thymidine kinase form of herpes simplex virus driven by myeloid- is translational regulation of the components of the translational apparatus; specific CD11b promoter and ganciclovir treatment as a tool, we selectively this would lead to an increase in translational rate that may persist. Indeed, ablated proliferating (Mac-2 positive) microglia after transient middle levels of S6 increase in synaptosomes in a rapamycin sensitive manner (Khan

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cerebral artery occlusion. The series of experiments using green fluorescent 283 B226 protein-chimeric mice demonstrated that within the first 72 h after ischemic THE ROLE OF ZINC IN PRESYNAPTIC RELEASE MECHANISMS injury, the Mac-2 marker [unlike Iba1 (ionized calcium-binding adapter AT THE HIPPOCAMPAL MOSSY FIBERS molecule 1)] was preferentially expressed by the resident microglia. Nathalie Lavoie and Katalin Tóth. Centre de Recherche Université Laval Selective ablation of proliferating resident microglia was associated with a Robert Giffard, Quebec City, Quebec marked alteration in the temporal dynamics of proinflammatory cytokine expression, a significant increase in the size of infarction associated with a The hippocampal mossy fiber (MF) axons arise from the dentate granule 2.7-fold increase in the number of apoptotic cells, predominantly neurons, cells of the dentate gyrus and provide synaptic input to neurons in the hilus and a 1.8-fold decrease in the levels of IGF-1. A double-immunofluorescence and the CA3 area of the hippocampus. One of the particularities of the MF analysis revealed a approximately 100% colocalization between IGF-1 terminals is their unusually high concentration of chelatable zinc in the positive cells and Mac-2, a marker of activated/proliferating resident synaptic vesicles. We have shown that zinc is necessary for the proper microglia. Conversely, stimulation of microglial proliferation after cerebral function of the presynaptic machinery. Indeed, chelation of vesicular zinc ischemia by M-CSF (macrophage colony stimulating factor) resulted in a decreases the frequency of spontaneous release and compromises the vesicle 1.9-fold increase in IGF-1 levels and a significant increase of Mac2+ cells. refilling machinery. In the present study, we aimed to investigate the Our findings suggest that a postischemic proliferation of the resident mechanisms by which zinc influences presynaptic release at the MF microglial cells may serve as an important modulator of a brain inflammatory terminals. Our data show that the potent membrane-permeable zinc chelator response. More importantly, our results revealed a marked neuroprotective DEDTC decreased the frequency of spontaneous EPSCs (sEPSCs) but had potential of proliferating microglia serving as an endogenous pool of virtually no effect in the presence of TTX (mEPSCs). This result could be neurotrophic molecules such as IGF-1, which may open new therapeutic explained by either a cellular mechanism which is only activated at higher avenues in the treatment of stroke and other neurological disorders. level of activity, or by an effect on presynaptic calcium dynamics allowing the synchronization of several release sites. In order to differentiate between these two possibilities, we have studied the effect of Brefeldin A (BFA) and 282 B225 caffeine on the spontaneous activity of CA3 pyramidal cells. BFA selectively INHIBITION OF CASPASE-MEDIATED APOPTOSIS BY blocks the AP3-dependent vesicle recycling pathway while caffeine increases PEROXYNITRITE IN TRAUMATIC BRAIN INJURY +C210 the intracellular calcium concentration. BFA-treatment (10µg/ml) selectively Lau A, Arundine M, Sun HS, Jones M, Tymianski M. Division of Fundamental decreased the frequency of sEPSCs with an amplitude higher then 100 pA, Neurobiology, Toronto Western Research Institute; Department of while sEPSCs with smaller amplitude were unaffected. It has been shown Physiology, University of Toronto; Department of Surgery (Neurosurgery), that zinc transport into vesicles (via specific transporter ZnT-3) seems to be University of Toronto related to the AP3 pathway. Therefore, we investigated whether the previously described effect of zinc chelation is still present in BFA-treated In traumatic brain injury (TBI), neurons surviving the primary insult may slices. Our data show that DEDTC does not change the frequency of sEPSCs succumb through poorly understood secondary mechanisms. In vitro, cortical in the presence of BFA. This suggests that the zinc-dependent presynaptic neurons exposed to stretch injury exhibited enhanced vulnerability to machinery and AP3-dependent endocytosis are overlapping intracellular NMDA, apoptotic-like DNA fragmentation, peroxynitrite (PN) formation, pathways. The application of caffeine (5mM) increased the frequency and the and cytoplasmic cytochrome c accumulation. Surprisingly, caspase-3 activity amplitude of sEPSPs in control slices and this effect was still present in was undetectable by both immunoblotting and fluorogenic activity assays. DEDTC-treated slices. These results suggest that zinc containing vesicles Therefore, we hypothesized that PN directly inhibits caspases in these are closely linked to the AP3-dependent endocytosis pathway and that the neurons. Consistent with this, stretch injury in cultured neurons elicited proper functioning of this pathway is crucial for the generation of large tyrosine nitration of procaspase-3, but not caspase-9 or Apaf-1, suggesting a amplitude events at the MF synapses. direct interaction of PN with caspase-3. In an ex vivo system, PN inhibited the activity of caspase-3, and this inhibition was reversible with the addition of the sulfhydryl reducing agent dithiothreitol, indicating that PN inhibits 284 B227 caspases by cysteinyl oxidation. Moreover, in cultures, the PN donor 3- VESICULAR ZINC INFLUENCES PRESYNAPTIC RELEASE AT morpholinosydnonimine (SIN-1) blocked staurosporine-induced caspase-3 THE MOSSY FIBER TERMINALS activation and its downstream effects including PARP-1 [poly-(ADP-ribose) Walter Rubio Alvarez*, Nathalie Lavoie* and Katalin Tóth. Centre de polymerase-1] cleavage and phosphotidylserine inversion, suggesting that Recherche Université Laval Robert Giffard, Québec City, Québec peroxynitrite can inhibit caspase-3-mediated apoptosis. To examine these mechanisms in vivo, rats were exposed to a lateral fluid percussion injury The hippocampal mossy fiber axons (MF) arise from the granule cells of (FPI). FPI caused increased neuronal protein nitration that colocalized with the dentate gyrus and provide synaptic input to neurons in the hilus and the TUNEL staining, indicating that PN was associated with neurodegeneration. CA3 area of the hippocampus. MF synapses have many unique anatomical Caspase-3 activity was inhibited in brain lysates harvested after FPI and was and physiological properties. The number of active zones and synaptic restored by adding dithiothreitol. Our data show that caspase-mediated vesicles that are stored in the presynaptic terminals are several folds higher apoptosis is inhibited in neurons subjected to stretch in vitro and to TBI in than in “conventional” synapses and MF inputs show very high degree of vivo, mostly because of cysteinyl oxidation of caspase-3 by PN. However, short-term facilitation. Another unique feature of this synapse is the this is insufficient to prevent cell death, indicating that the TBI therapy may, unusually high level of chelatable zinc in the synaptic vesicles. It is not at a minimum, require a combination of both anti-apoptotic and anti-oxidant currently known why MF terminals contain such a high concentration of zinc strategies. and whether there is a correlation between the unique physiological properties of this synapse and their zinc content. In the present study, we aimed to investigate how the presence of zinc in the presynaptic vesicles affects presynaptic release at the mossy fiber terminals. We have used membrane-permeable (DEDTC) and membrane- impermeable (CaEDTA) zinc chelators to differentiate between the effect of synaptically released and vesicle-bound zinc. Recordings from CA3 pyramidal cells showed a decrease of spontaneous activity (sEPSCs) with the application of DEDTC, while CaEDTA had no effect. Recordings from CA1

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pyramidal cells showed no change in activity which demonstrates that Mammalian Staufen1 (Stau1) is an RNA-binding protein involved in DEDTC effect is specific to CA3 terminals. Sucrose puffs application to mRNA transport, localization and translational control. Stau1 is present in DEDTC-treated slices also showed a decrease in the readily release pool RNA granules transported along hippocampal neuron dendrites. This (RRP), an effect not seen with CaEDTA. Next, we evoked MF and dendritic mRNA localization may be critically involved in long-term associtational/collateral (AC) synaptic inputs with focal stimulation. While synaptic plasticity and memory. Thus, our aim was to investigate the DEDTD did not influence basal transmission, high frequency frequency was implication of Stau1 in synaptic plasticity of hippocampal pyramidal cells. less efficient in the absence of vesicular zinc from MF input (DCG-IV We used RNA interference (siRNA) to examine effects of Stau1 down- sensitive). Responses evoked with the stimulation of AC inputs (DCG-IV regulation in hippocampal slice cultures. We established by western blot insensitive) were insensitive to DEDTC. Both basal transmission and short- analysis the efficacy and specificity of biolistic transfection of Stau1 siRNA term plasticity were unaffected by the presence of the zinc chelators. on Stau1 expression in HEK293 cells and in hippocampal slice cultures. These data suggest that the major role of zinc at the mossy fiber terminals is Recordings of field EPSPs were used to assess effects of Stau1 down- not the regulation of postsynaptic receptors as it was believed previously, but regulation on pyramidal cell synaptic plasticity. We observed a block of the it is necessary for the proper function of the unique presynaptic release late form of long-term potentiation (L-LTP) induced by forskolin. The early machinery. form of tetanus-induced LTP, mGluR1-induced long-term depression (LTD), * These authors contributed equally to this work. and basal evoked synaptic transmission were unaffected by Stau1 down- regulation, suggesting an implication of Stau1 in transport of newly synthesized mRNA to activated synapses for local protein synthesis 285 B228 associated with L-LTP. Using whole cell recordings of miniature EPSCs THE EFFECT OF ZINC ON THE ULTRASTRUCTURE OF (mEPSCs), we found a decrease in mEPSC amplitude and frequency after PRESYNAPTIC MOSSY FIBER TERMINALS Stau1 down-regulation. Thus, Stau1 is also involved in regulation of László Seress 1, Modesto R. Peralta III 2 and Katalin Tóth 2. 1) University spontaneous activity at excitatory synapses. Confocal microscopy was used of Pécs, Faculty of Medicine,Central Electron Microscopic Laboratory, to study the impact of Stau1 siRNA on dendritic spine morphology in EYFP- Pécs, Hungary; 2) Centre de Recherche Université Laval Robert Giffard, labelled CA1 pyramidal cells. We observed no change in spine density, but Québec City, Québec found a decrease in regular spines and an increase in elongated spines, as well as an increase in filopodia protrusions after Stau1 down-regulation. The Zinc in the mossy fiber terminal is localized in synaptic vesicles. It was shift from regular to elongated spine morphology is consistent with the L- suggested that during synaptic transmission it is released and translocates to LTP impairment, whereas the increase in filipodia protrusions is consistent the postsynaptic cell. We investigated this possibility using a highly sensitive with the reduction in spontaneous synaptic activity...... These results reveal sodium tungstate Timm method to detect vesicular zinc at the electron new roles for Stau1 in mRNA transport to synapses to maintain efficacy of microscopic level. Since our previous data showed that zinc in the spontaneous activity and to sustain long-term increases in synaptic strength presynaptic terminals can influence release properties, we investigated the during LTP. This Stau1 regulation of development and long-term plasticity of effect of zinc chelation on the size of the vesicle pool and on the distribution hippocampal pyramidal cell synapses and dendritic spines may be important of presynaptic vesicles. First, we visualized zinc content in pre- and for the functional connectivity changes underlying hippocampal-dependent postsynaptic elements in control and epileptic animals. This method produces learning and memory. round silver grains that are small enough to precisely locate zinc both inside synaptic terminals and in the synaptic cleft. Our data showed in control animals zinc-staining was restricted to presynaptic vesicles, staining was 287 B230 absent from the synaptic cleft. Zinc-staining was decreased after epileptic SMALL PEPTIDOMIMETIC LIGANDS OF NEUROTROPHIN seizures inside the terminals and increased on the presynaptic membrane RECEPTORS REGULATE RETINAL GANGLION CELL DEATH IN surface. However, staining on the postynaptic membrane or in the VIVO: A ROLE FOR MÜLLER CELL-SPECIFIC P75NTR? postsynaptic cell was not observed either in control, or in epileptic animals. Frédéric Lebrun-Julien1, Horacio Uri Saragovi 2, Adriana Di Polo1.. Next, we chelated zinc with DEDTC before seizure induction to measure the 1Pathology/Cell Biology, University of Montreal, Montreal; 2Pharmacology size of the readily-releasable and total vesicle pool in the absence of zinc in and Therapeutics, Lady Davis Research Institute, McGill University, the synaptic terminal. We calculated vesicle density in 4 identified Montreal compartments in mossy fibre terminals. Each compartment was 75 nm wide, and the first compartment bordered with the active zone. We found that The neurotrophins play important roles in the survival of central nervous vesicle density was significantly decreased in all 4 compartments, the most system neurons. Two classes of cell surface receptors mediate the biological significant effect was observed in the first compartment. These data indicate effect of mature neurotrophins: the Trk family of receptor tyrosine kinases that zinc can be visualized on the presynaptic membrane surface in an and p75NTR, which binds all neurotrophins. Sortilin, the latest neurotrophin activity-dependent manner, and the level of zinc inside the terminal is also receptor to be identified, interacts preferentially with pro-neurotrophins. In modified by increasing synaptic activity. In the absence of zinc the number the adult retina, TrkA is expressed by adult retinal ganglion cells (RGCs), of vesicles is decreased, indicating that refilling the large vesicle pool in while p75NTR is exclusively expressed by Müller glia. Here we used small mossy fibre terminals during/following high level synaptic activity requires and proteolytically stable ligands of neurotrophin receptors, with receptor a zinc-dependent machinery. selective activity, to unmask the role of each receptor in RGC survival. Peptidomimetic ligands (agonist or antagonist: 1 µg/µl) were independently injected or co-injected into the vitreous chamber of adult Sprague-Dawley 286 B229 rats at the time of optic nerve transection. For analysis of neuronal survival, STAUFEN REGULATES LONG-TERM SYNAPTIC PLASTICITY, RGCs were retrogradely labeled by application of FluoroGold in the superior SPONTANEOUS SYNAPTIC ACTIVITY AND SPINE colliculus, the main target region of RGCs in the rodent brain. Neuronal MORPHOLOGY IN HIPPOCAMPAL PYRAMIDAL CELLS survival was quantified at 1 or 2 weeks after nerve injury. Our data Geneviève Lebeau1*, Marjolaine Maher-Laporte2, Lisa Topolnik1, Charles demonstrate that specific activation of TrkA by a peptidomimetic agonist E. Laurent1, Wayne Sossin3, Luc DesGroseillers2 and Jean-Claude (D3) led to marked neuroprotection of axotomized RGCs, while intraocular Lacaille1. 1Départements de physiologie, et 2biochimie, Groupe de administration of recombinant nerve growth factor (NGF) did not promote recherche sur le système nerveux central, Université de Montréal, Montréal survival. Combination of D3 with a TrkA antagonist completely inhibited its and 3Department of Neurology and Neurosurgery, McGill University, neuroprotective effect. Remarkably, a single injection of a p75NTR receptor Montreal

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antagonist promoted robust RGC survival after axotomy. Our results also Cyclodextrin (MBCD) reduces membrane cholesterol and inhibits the extent, demonstrate activation of the transcription factor nuclear factor kappa-B Ca2+-sensitivity and kinetics of fusion of cortical vesicles from sea urchins (NF-kB), a downstream effector of p75NTR, in the axotomized retina. In (Churchward et al, J. Cell Sci. 118:4833-48, 2005). In crayfish muscle, addition, we show that sortilin, which can induce cell death by interacting MBCD increases spontaneous quantal release and decreases the amplitude of with p75NTR in the presence of pro-neurotrophins, is specifically expressed excitatory junctional potentials (EJPs) by blocking impulse propagation by Müller glia and is upregulated in these cells after injury. Collectively, our (Zamir & Charlton, J. Physiol. 571.1: 83-99, 2006). Thus, cholesterol may data demonstrate a neuroprotective effect of novel, small peptidomimetic influence the release pathway in many ways. We examined a possible effect ligands of neurotrophin receptors in the retina, and suggest that Müller cells of temperature acclimatization on responses to MBCD in deep abdominal are involved in the regulation of RGC death via a p75NTR-dependent extensor muscles of the crayfish, Procambarus Clarkii. Crayfish were mechanism. housed at 20ºC or at 14º C for 2-12 weeks, after which EJPs were recorded at room temperature to assess effects of MBCD. EJP amplitudes from cold acclimatized crayfish decreased by 15.7 ± 11.2 % in the presence of 10 mM 288 B231 MBCD, which was almost significantly different from cold controls without MULTIPLE GBETAGAMMA MEDIATED PRESYNAPTIC MBCD (-2.8 ± 5%; p = 0.056, n = 9). In 5 of 9 warm acclimatized animals, INHIBITORY PATHWAYS OF VESICLE RELEASE BETWEEN however, MBCD actually increased EJP amplitude. The overall change in SYNAPTICALLY PAIRED IDENTIFIED LYMNAEA NEURONS EJP amplitude for warm acclimatized animals was 3.8 ± 2.9% in response to Lee DWK*, Guo C, Feng ZP. Dept. of Physiology, University of Toronto MBCD, compared to -6.8 ± 5.6% for warm acclimatized controls (p = 0.034, n = 9). Thus, effects of this cholesterol chelator on EJP amplitude appear to Synaptic transmission involves the exocytosis of presynaptic vesicles, a depend on acclimatization temperature in crayfish. Supported by NSERC. process that is susceptible to modulation through the activation of presynaptic G-protein coupled receptors (GPCR). It is believed that GPCR activation leads to a pathway involving the G-protein subunit Gbetagamma, 290 C201 but the mechanisms involved are not fully understood. This study examined COMBINED ENVIRONMENTAL ENRICHMENT AND EXERCISE Gbetagamma-mediated calcium channel dependent and independent CAUSES AN INCREASE IN NEURONAL PROLIFERATION AND inhibitory pathways on presynaptic vesicle release between synaptically PARTIALLY REPAIRS THE INJURED HIPPOCAMPUS paired identified Lymneaea stagnalis neuons; the presynaptic neuron VD4, Hugo Lehmann, Simon Spanswick, Robert J. Sutherland. Canadian Centre which possesses dopamine (DA) GPCRs, and postsynaptic neuron LPeD1. for Behavioural Neuroscience, University of Lethbridge, Lethbridge Exogenous application of DA onto the presynaptic VD4 neuron reduced EPSC amplitudes recorded from the postsynaptic LPeD1 neuron. To The dentate gyrus subfield of the hippocampus is one of two regions in determine if this reduction was due to inhibition of presynaptic vesicle the adult mammalian brain that continues to produce neurons. We examined release, VD4 neurons were labeled with FM1-43 dye. VD4 neurons whether these new neurons could replenish a partially damaged dentate gyrus stimulated to fire APs showed reduced FM1-43 unloading in the presence of and reverse damage-related cognitive deficits. Rats acquired two different DA. This inhibition could be attenuated by acute knockdown of Gbeta using types of memory (spatial and context memory) and then were given bilateral double stranded RNA (Gbeta-dsRNA). These findings suggest that DA adrenalectomy (ADX). ADX dramatically decreases circulating activates a Gbetagamma dependent inhibitory pathway of presynaptic vesicle corticosterone levels, which causes a slow degeneration of the granule cell release. To test whether DA activated a Gbetagamma-mediated calcium layer of the dentate gyrus. Ten weeks after ADX, a period sufficient to cause channel dependent inhibitory pathway of vesicle release, simultaneous significant damage to the dentate gyrus, rats were placed on a regimen of whole-cell voltage-clamp recordings with ratiometric FURA-2 calcium corticosteroid replacement and a 6-wk protocol of environmental enrichment imaging of VD4 neurons were used. DA reduced the whole cell VD4 calcium and exercise in running-wheels. The latter protocol is known to increase currents as well as intracellular calcium concentrations. The reduction in proliferation and survival of neurons in the dentate gyrus. Rats were then calcium currents could be partially removed by a depolarization pre-pulse. tested for retention of both types of memory. On the spatial memory test Acute knockdown of Gbetagamma using Gbeta-dsRNA reduced the DA- conducted in the Morris water task, rats that had received ADX remembered mediated inhibition and abolished the prepulse relief, confirming that the location of the hidden platform as well as control rats. In contrast, ADX Gbetagamma inhibits calcium channels in VD4. To test the calcium channel rats were impaired on the context memory test. They displayed less freezing independent pathway of Gbetagamma mediated inhibition, the ionophore than control rats in the context that was previously associated with a fear- ionomycin was used to permit calcium influx independently from calcium eliciting event. The combined environmental enrichment and wheel running channels to study vesicle release. DA inhibited ionomycin induced FM1-43 treatment did not reverse the cognitive deficits that were caused by the ADX release. This inhibitory effect was attenuated after knockdown of Gbeta and related dentate gyrus damage. Nevertheless, the combined environmental suggesting that Gbeta inhibits vesicle release in a calcium channel enrichment and wheel running protocol was successful in increasing independent manner. This suggests that Gbetagamma possesses multiple neuronal proliferation in the dentate gyrus and this increase tended to pathways for inhibiting vesicle release within the same cell upon dopamine repopulate the granule cell layer of the dentate gyrus. Therefore, we have a receptor activation. Future study will be carried out to determine the model that enables the examination of replacing neurons in the injured contribution of both Gbetagamma mediated inhibitory pathways on vesicle hippocampus and its effect on cognition. release in these neurons.

291 C202 289 B232 MIGRATION OF NEURONAL PRECURSORS IN THE ADULT EFFECTS OF A CHOLESTEROL CHELATOR ON SYNAPTIC BRAIN IS MODULATED BY GABAERGIC SIGNALLING AND TRANSMISSION IN CRAYFISH DEPEND ON ACCLIMATIZATION CA2+ ACTIVITY TEMPERATURE Morgane Lemasson*, Andre Parent and Armen Saghatelyan. Centre de *Amanda M. Lehmann1, Jens Coorssen2, A. Joffre Mercier1. 1Dept. of recherche Universite Laval Robert-Giffard, 2601, Chemin de la Canardiere, Biological Sciences, Brock University, St. Catharines; 2Dept. of Physiology Quebec & Biophysics, University of Calgary, Calgary Adult olfactory bulb (OB) has a remarkable capacity to renew its Cholesterol is an integral part of cell membranes and a major component interneuronal population throughout the entire life-span of animals, including of vesicle membranes. The cholesterol chelator Methyl-β-

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humans. The neuronal precursors are produced in the subventricular zone regulatory domains. The mutation H282K, which mimics the increased (SVZ) and have to migrate tangentially, in chains, ensheathed by astrocytic protonation of His (pKa ~6.3) that occurs during a physiological decrease in processes, in the rostral migratory stream (RMS) to reach the OB. To better pHi, facilitated GFP-CaMKII clustering. These results suggest that the Ca2+- understand the mechanisms of neuronal migration in adult forebrain we have dependent drop in pHi during synaptic activity promotes the clustering of established a time-lapse videomicroscopy combined with Ca2+ imaging in CaMKII at the PSD, which may have a role in mechanisms of synaptic the acute slices of adult mouse brain. We have observed fast (80-150 plasticity. μm/hour), saltatory migration of neuronal precursors with active phases of neuronal displacement interspersed amongst resting periods. Interestingly, the duration of migratory phases was correlated with the 293 C204 spontaneous Ca2+ fluctuations in non-migrating cells. These non-migrating PDGFR RECEPTORS TARGET NR2B-CONTAINING NMDA cells are most likely astrocytes since i) together with neuroblasts they RECEPTORS IN THE HIPPOCAMPUS represent about 90% of cells in the adult RMS and ii) they do not migrate Aeni Lim 1, Michael Beazely 1, John F. MacDonald 1,2. Departments of throughout the entire period of recording (more than 1 hour). Interestingly, 1Physiology, 2Pharmacology, University of Toronto a temperature drop of 32ºC to 22ºC decreased the frequency of Ca2+ fluctuations by 67% and blocked neuronal migration. These results suggest Glutamate is the primary transmitter at excitatory synapses in neurons, that Ca2+ activity in astrocyte-like cells play a crucial role in the tangential however excess glutamate levels can result in the death of neurons in the migration of adult neuronal precursors. Thereafter, we sought to determine CNS by over-activating glutamate-gated ion channels such as the NMDA what triggers these Ca2+ fluxes in the astrocyte-like cells. Since neuronal receptor (NMDAR). When NMDARs are activated, NMDARs increase precursors in the adult RMS synthesize GABA and astrocytes contain postsynaptic calcium level and activate signaling cascades including the GABAA receptors, we hypothesized that neuroblasts themselves control extracellular signal-regulated kinase (ERK) and cyclic AMP response Ca2+ activity in astrocytes through gabaergic signaling. To explore this element binding protein (CREB) pathways. Focal ischemia in rat brain is possibility and to block endogenous gabaergic signaling we applied the associated with a rapid (3 hr) increase in the mRNA transcripts of PDGF-B GABAA receptor antagonist, bicuculline. Application of bicuculline chain isoforms that peaks at 24 hours. PDGFβ receptor expression decreased the frequency of the Ca2+ fluxes in astrocyte-like cells by 41% levels (but not mRNA) also rise rapidly after ischemia in rat brain. and affected the migration of neuronal precursors in the RMS. Altogether, Furthermore, neuronal death in hippocampal cultures after exposure to high these results suggest that adult neuronal precursors control their own levels of glutamate or NMDA can be attenuated by 24 hr pretreatment with migration via release of GABA that triggers Ca2+ fluctuation in the PDGF-BB. NR2B-containing NMDARs may localize to primarily extra- neighboring astrocytes. synaptic compartments and mediate the excitotoxic effects of ischemia and excess glutamatergic signaling. In contrast, NR2A-containing NMDARs are primarily synaptic and signaling through these receptors may be 292 C203 neuroprotective. To examine the mechanisms of PDGF-BB neuroprotection, A CHANGE IN POST-SYNAPTIC pH DURING SYNAPTIC we examined the localization of PDGFβ receptors in cultured TRANSMISSION REGULATES CaM KINASE II hippocampal neurons. PDGFβ receptors do not colocalize with the TRANSLOCATION post-synaptic protein, PSD-95. Preliminary evidence suggests a higher M. Lemieux, É. LeBel, P. De Koninck. Neurobiologie cellulaire, Centre de colocalization of PDGFβ receptors with the NR2B NMDA subunit. recherche Université Laval Robert-Giffard, Université Laval, Québec PDGF-BB treatment of hippocampal slices and cultured hippocampal neurons resulted in a decrease in the membrane localization of NR2B, but did The multifunctional Ca2+/calmodulin protein kinase II (CaMKII) is a not affect membrane localization of either NR1 or NR2A subunits. This work key enzyme in the signaling processes that underlie synaptic plasticity at may suggest that neuroprotective effects of PDGF-BB treatment of excitatory synapses. The dynamic translocation of CaMKII in and out of hippocampal neurons may be due to a preferential decrease in the activity of synapses, regulated by its remarkable structural and regulatory properties, extrasynaptic NR2B-containing NMDA receptors. might control this plasticity. Others and we have reported that a brief (< 1 min) activation of NMDA receptors in neurons leads to the activation of CaMKII and its translocation to the postsynaptic density (PSD). We also 294 C205 reported that a sustained activation of NMDA receptors (> 2 min) can cause PRENATAL INFLAMMATION AND DISRUPTED HIPPOCAMPAL an intracellular clustering of the kinase. This process is reminiscent of a FUNCTION CaMKII self-association mechanism, which, in heterologous cells, depends Germaine Lowe*, Giamal N Luheshi, Sylvain Williams. Douglas Hospital on both a rise in free Ca2+ and a decrease in intracellular pH (pHi). Previous Research Center, Department of Psychiatry, McGill University, Montreal evidence indicates that NMDA receptor activation in neurons induces a Ca2+-dependent intracellular acidification. The aim of this study is thus to Prenatal exposure to infection during a critical period for fetal brain determine whether i) CaMKII intracellular clustering and ii) translocation to development has been linked to increased risk for schizophrenia, suggesting the PSD evoked by NMDA receptor activation are regulated by pHi. Using that a portion of schizophrenia could be due to neurodevelopmental live imaging of wild type and mutated constructs of GFP-CaMKII, disruptions. The human hippocampus is compromised in schizophrenia and fluorescent Ca2+ and pH indicators, we are monitoring CaMKII it is unknown whether these changes are due to neurodevelopmental translocation and variations of free cytosolic Ca2+ and pHi in cultured rat alterations. Here we used bacterial endotoxin lipopolysaccharide (LPS) to hippocampal neurons. To evaluate post-synaptic pH, we also transfect simulate bacterial infection and stimulate the maternal inflammatory neurons with a genetically-encoded fluorescent indicator that targets to the response during a critical period in pregnancy (i.e., second trimester) for PSD. To control variations in pHi, we use extracellular application of NH4Cl hippocampal development in the fetus. We administered 100µg/kg LPS to or patch clamping with pH buffers. Our preliminary results 1) confirm that pregnant rats on gestation days 15 and 16 (gestation = 21 days) and recorded NMDA receptor stimulation causes a significant drop in pHi in extracellular responses in slices from the hippocampus of the offspring at somatodendritic regions; 2) indicate that post-synaptic pH also drops upon PD20-25 to evaluate hippocampal synaptic transmission. Schaeffer stimulation; and that 3) extracellular application of NH4Cl prevents both the collateral-evoked field excitatory postsynaptic potentials (fEPSPs) in area evoked drop in pHi and the intracellular clustering of GFP-CaMKII. To CA1 were significantly greater in amplitude and slope in offspring from identify pH sensitive residues on the kinase, we are testing site-directed LPS-treated dams (2.18 ± 0.25mV; 0.96 ± 0.11mV/ms) compared to those mutations near its catalytic site. His 282 is at the hinge of the catalytic and recorded from offspring of saline-injected dams (1.44 ± 0.14mV; 0.65 ±

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0.08mV/ms). This effect was unique to the CA1 area since it was not Long-term potentiation refers to the increase in synaptic strength observed in CA3 or dentate gyrus. However, input-output curves revealed following repetitive, high-frequency stimulation of excitatory synapses that a greater amount of current applied to Schaeffer collaterals was required (Lomo, 1966; Bliss & Lomo, 1973). This synaptic enhancement lasting hours to evoke an equivalent amplitude in the fEPSP in the LPS group compared to to days is the postulated corollary of learning and memory and although it saline. In CA1, changes in paired-pulse facilitation of the fEPSP, a measure was initially demonstrated in the hippocampus, this activity-dependent of presynaptic transmitter release, were not found. Fast GABAergic synaptic alteration is a fundamental property of most excitatory synapses in inhibition of CA1 pyramidal neurons was not found to be disrupted in the the mammalian brain (Sun, Zhao, & Wolf, 2005). An increase in the number LPS group when evaluated by paired-pulse inhibition of the population and the conductance of postsynaptic (S)-a-amino-3-hydroxy-5- spike. The intrinsic excitability of CA1 pyramidal neurons was heightened methylisoxazole-4-proprionic acid receptors (AMPARs), a class of because antidromic responses in the LPS group (9.41 ± 1.84mV) were glutamate receptor, has been shown to underlie LTP (Isaac, Nicoll, & significantly larger than those in control (2.86 ± 1.13mV). This increased Malenka, 1995; Lynch & Beaudry, 1984). Despite what knowledge has been excitability observed in field recordings was also found in whole-cell patch- gained, the complex molecular mechanisms by which LTP is accomplished clamp recordings of CA1 pyramidal cells, which revealed a more depolarized are not fully elucidated and the list of AMPAR protein partners is by no resting membrane potential in LPS group (–56.09 ± 0.84mV) compared to means complete. those in saline (-58.90 ± 0.33mV). These results show that Parkin, a 465 amino acid E3 ubiquitin ligase that mediates the attachment neurodevelopmental disruption triggered by prenatal inflammation can have of ubiquitin onto substrate proteins targeting them for degradation by the 26S profound effects on hippocampal synaptic transmission and could likely proteasome, is a synaptic protein containing a PDZ-domain binding motif contribute to the memory and cognitive deficits observed in schizophrenia. that associates with NR2B and CAMKII, components of the glutamate receptor-signalling complex (Fallon et al., 2002). Reduced synaptic strength has been demonstrated in cortico-striatal sections from Parkin KO mice 295 C206 (Goldberg et al., 2003). Further, Parkin inhibits PTEN, which negatively LONG-TERM EXPOSURE TO BRAIN-DERIVED NEUROTROPHIC regulates the PI3K/AKT pathway (Yang et al., 2005). PI3K associates with FACTOR INDUCES SPECIFIC CHANGES IN INHIBITORY AMPARs at the synapse and mediates translocation of AMPARs to the SYNAPTIC TRANSMISSION IN RAT DORSAL HORN NEURONS synapse and hence LTP (Man et al., 2003). In the current study, we examined Van B. Lu*, William F. Colmers and Peter A. Smith. Department of the effect of Parkin on post-synaptic AMPAR translocation (i.e., LTP) Pharmacology, University of Alberta, Edmonton following stimulation with KCl. Using a synaptosome-based system that retains the molecular machinery necessary for synaptic transmission, Neuropathic pain is a disease of abnormal and inappropriate pain specifically pre- and post-synaptic membranes, we compared chemically- signaling. It can arise from damage to the nerves that transmit pain signals to induced LTP in WT versus Parkin KO mice. Over various durations of KCl the brain either through disease, infection or trauma. Unfortunately, exposure, the number of surface AMPARs increased linearly in the WT conventional analgesics such as the NSAIDs and opioids are not very synaptosomes. Despite similar quantities of surface AMPARs at baseline, effective in managing neuropathic pain. Therefore, the mechanisms and there was no increase in surface AMPAR number over longer durations of mediators involved in instigating neuropathic pain are attractive new KCl exposure, hence no LTP in the Parkin-KO derived synaptosomes. We therapeutic targets for the treatment of this disease. Brain-derived speculate that Parkin affects synaptic AMPAR trafficking by disinhibiting the neurotrophic factor (BDNF), which can induce long-lasting neuronal PI3K-AKT pathway. Studies to directly investigate this hypothesis are changes, has been implicated as a mediator of neuropathic pain. We have planned. previously shown that long-term exposure of dorsal horn neurons to BDNF increases excitatory synaptic transmission to putative excitatory neurons whilst decreasing that to inhibitory neurons. Here we investigated the effects 297 C208 of long-term BDNF exposure on inhibitory synaptic activity in dorsal horn ANOMALOUS EFFECT OF LI+ ON KAINATE RECEPTORS neurons by recording and analyzing spontaneous inhibitory post-synaptic David M. MacLean, Adrian Y.C. Wong, Anne-Marie Fay and Derek Bowie. currents (sIPSCs). Whole-cell recordings were obtained from dorsal horn Dept. of Pharmacology and Therapeutics, McGill University neurons in organotypic cultured slices (OTCS) incubated with 200ng/ml of BDNF for 5-6 days. Age-matched, untreated OTCS served as controls. Our lab has recently shown that, in addition to the neurotransmitter L- Dorsal horn neurons were classified based on their action potential discharge Glutamate, kainate-selective glutamate receptors (KARs) have an absolute firing pattern during depolarizing current steps. Generally, the frequency of requirement for external ions. In addition, the decay kinetics of the receptor sIPSCs was affected the most following long-term BDNF treatment. are strongly dependent on the type of external ion present. While examining However, alterations in inhibitory synaptic activity were not uniform across interactions between external cations and KAR agonists, we uncovered a all classes of dorsal horn neurons. In ‘tonic’ and ‘phasic’ neurons, both novel ability of Li+ to regulate the gating properties of GluR6 KARs. exhibited a significant decrease in sIPSC frequency with an increase in Specifically, we found that replacement of extracellular Na+ with Li+ sIPSC amplitude (KS-test, p<0.05) following long-term BDNF exposure. produced three effects that were only observed with the agonists kainate Other classes of dorsal horn neurons, like the ‘delay’ and ‘transient’ single- (KA) and domoate (Dom): (1) an increase in the relative peak response, (2) spiking neurons, displayed a significant increase in sIPSC frequency a slowing of decay kinetics, (3) and a substantial increase in the relative following long-term BDNF treatment (KS-test, p<0.001) but no change in equilibrium response. Interestingly, KA and Dom possess structural sIPSC amplitude (KS-test, p>0.5). These results together with the effects of similarities, specifically a pyrrolidine ring about the α-amine group long-term BDNF exposure on excitatory synaptic activity illustrate the which is not found in other KAR agonists, suggesting that this element of the complexity of BDNF’s effects on dorsal horn neurons. Funding support from ligand’s structure may be necessary for Li+’s effects. Cations exert their CIHR and AHFMR. effects on KARs by binding to or near the M770 residue and the introduction of a surrogate cation into this position (ie. a K or R residue) blocks ion- dependent gating. Surprisingly, agonist-dependent modulation by Li+ 296 C207 persisted in the M770K mutation, suggesting that Li+ binds to a distinct site THE EFFECT OF PARKIN ON LONG-TERM POTENTIATION of the receptor. We identified a mutation (K531A) in the dimer interface, a Penny A. MacDonald*, Amadou T. Corera, Edward A. Fon. Department of region known to be involved in desensitization, which occluded the agonist Neurology and Neurosurgery, McGill University; Center for Neuronal specific effect of Li+. However, it is not yet known if K531 represents a Survival, McGill University structural element necessary for the binding of Li+. Moreover, whether the

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Li+ site only becomes accessible following activation by KA and Dom ± 4% of control, p<0.05) but surprisingly no change in frequency of mEPSCs remains an open question. (97 ± 13% of control) nor in the AMPA/NMDA ratio, the latter suggesting a proportional increase in both AMPA and NMDA receptor-mediated synaptic transmission. Interestingly the decrease in synapse number was not 298 C209 accompaigned by a decrease in mEPSC frequency, suggesting a CLIMBING FIBRE CONTROL OF PURKINJE CELL SPIKE compensatory change in the probability of vesicular release. Moreover, we OUTPUT found that the observed morphological and functional changes were Bruce E. McKay*, Jordan D. Engbers, W. Hamish Mehaffey, Grant R.J. associated with altered bidirectional synaptic plasticity. In conclusion the Gordon, Michael L. Molineux, Jaideep S. Bains and Ray W. Turner. continued activation of AMPA receptors is necessary for maintaining the Hotchkiss Brain Institute, University of Calgary, Calgary structure and function of glutamatergic synapses.

Purkinje cells integrate multimodal afferent inputs and generate the sole output of the cerebellar cortex. Via their control over deep cerebellar nuclear 300 C211 neurons, they shape the final outflow of information from the cerebellum to CALCIUM-INDEPENDENT PHOSPHOLIPASE A2 INFLUENCES regulate a variety of motor- and learning-related behaviours. The AMPA-MEDIATED TOXICITY OF HIPPOCAMPAL SLICES BY contributions of Purkinje cells to these functions are modified by both acute REGULATING GLUR1 SUBUNIT IN SYNAPTIC MEMBRANES and chronic effects of climbing fibre (CF) afferents. Whereas the chronic Caroline Ménard*, Anne-Marie Gagné, Christian Patenaude and Guy effects of CF discharge, such as the depression of conjunctively activated Massicotte. Groupe de recherche en neurosciences, Département de chimie- parallel fibre inputs, are well established, the acute effects of CF discharge biologie, Université du Québec à Trois-Rivières, Trois-Rivières, Québec and their associated mechanisms remain poorly understood. Here we show that CF discharge presented at physiological frequencies substantially Over the last decade, several studies have documented that alterations in modifies the frequency and pattern of Purkinje cell spike output in in vitro rat calcium-independent phospholipase A2 (iPLA2) activity is associated with cerebellar slices. CF discharge converts an intrinsically-generated trimodal development of neurodegenerative disorders. The iPLA2 enzymes were pattern of output characteristic of Purkinje cells in vitro to a more naturalistic found to interact with alpha-amino-3-hydroxy-5-methylisoxazole-4- pattern composed of spike trains interrupted by short and long CF-evoked propionate (AMPA) receptor function and the recent results obtained on pauses and state transitions. The effects of CF discharge could be reproduced glutamate receptor phosphorylation point to the hypothesis that iPLA2 in the presence of synaptic blockers using current injections to simulate CF / systems could influence glutamate-induced toxicity in the brain. Experiments complex spike depolarizations, revealing that CF modification of Purkinje described here, using cultured hippocampal slices, examined this notion by cell output is not a product of network activity. Instead, we found that investigating whether iPLA2 inhibition can interfere with AMPA receptor postsynaptic changes in the Purkinje cell, produced at least by an interplay properties and toxicity. We observed that preincubation of organotypic between sodium channels and calcium-activated potassium channels, hippocampal slices with the iPLA2 inhibitor bromoenol lactone (12 h; 3 µM) accounted for CF-mediated effects on spike output. Furthermore, by increased the phosphorylation on both Ser831 and Ser845 sites of GluR1 controlling the frequency of Purkinje cell spike output over three discrete subunits of AMPA receptors, but did not affect phosphorylation on NR1 levels, CF discharge modulates the gain of Purkinje cell responsiveness to subunit of N-methyl-D-aspartate (NMDA) receptors. Also, GluR1 subunit parallel fibre inputs in vitro. The three frequencies of CF-controlled output phosphorylation levels were selectively increased by (R)-BEL, an further proved to differentially regulate the output of deep cerebellar nuclear enantioselective inhibitor of iPLA2γ, but not by (S)-BEL, an neurons, revealing that CFs may act as a cortico-nuclear switch that either iPLA2β inhibitor. Overtime, the iPLA2γ inhibitor (R)-BEL restricts Purkinje cell signaling to the cerebellar cortex or enables Purkinje promoted the insertion of new GluR1 subunits into synaptic membranes, an cell output to influence the entire cortico-nuclear axis. These findings effect observed by differential centrifugation and independent biotinylation provide important insights into the probable cellular and network factors experiments. Here again, NR1 subunit level was unaffected by (R)-BEL contributing to motor disturbances following CF denervation. treatment. Finally, inhibition of iPLA2γ exacerbated AMPA-mediated cell death in the CA1 region of the hippocampus, an effect that was selectively abolished by IEM 1460 and philanthotoxin-433, two antagonists 299 C210 specific for AMPA receptors lacking GluR2 subunits. These results provide STRUCTURAL AND MORPHOLOGICAL EFFECTS OF CHRONIC evidence that iPLA2γ-related regulation of AMPA receptor GluR1 AMPA RECEPTOR BLOCKADE IN HIPPOCAMPAL SLICE subunit phosphorylation could represent an important mechanism CULTURES modulating hippocampal cell death induced by AMPA receptor stimulation. José María Mateos1, Andreas Lüthi2,, Natasa Savic1, B. H. Gähwiler1 and This investigation raises the possibility that iPLA2 mechanisms might R. Anne McKinney1,3. 1. Brain Research Institute, University of Zurich, 2. contribute to neurodegenerative processes. Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland 3. Department of Pharmacology and Therapeutics, McGill William-Osler, Montreal 301 C212 DIFFERENTIAL EXPRESSION OF SYNAPTOTAGMIN ISOFORMS The maintenance of dendritic spines, the postsynaptic elements of IN DOPAMINE NEURONS AND ITS IMPLICATION IN glutamatergic synapses, within the CNS require continued activation of SOMATODENDRITIC DOPAMINE RELEASE AMPA receptors. In organotypic hippocampal slice cultures, chronic J. Alfredo Mendez, Marie-Josée Bourque, Louis-Eric Trudeau. Department blockade of AMPA receptors for 14 days induced a significant loss of of Pharmacology, CNS Research Group, Faculty of Medicine, Université de dendritic spines on CA1 pyramidal cells. Here, using serial section electron Montréal, Montreal microscopy we show a loss of spines paralleled by a significant loss of asymmetric synapses. We observed an increase in the number of asymmetric Active mesencephalic dopamine (DA) neurons release DA in their shaft synapses, suggesting that spine retraction does not necessary lead to terminal projection areas as well as locally within the mesencephalon synapse elimination. As the dendritic spines are the primary targets of through somatodendritic (STD) release. STD release of DA has been shown excitatory glutamatergic inputs, we investigated how a decrease in spine to regulate DA neuron firing through D2 autoreceptor activation and may be density and an increase in the number of shaft synapses affect synaptic implicated in motor performance regulation. Under normal circumstances, transmission. We observed a significant increase in mEPSC amplitude (119 this form of release appears to require some form of exocytosis. Compatible

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with this, STD DA release is TTX-sensitive, calcium-dependent, sensitive to molecular mechanisms underlying intracellular retention of α7 depletion of vesicular stores by reserpine and more importantly, blocked by subunits, and more clearly examine regulation of their trafficking. treatment with botulinum toxins that cleave SNARE proteins. Interestingly, STD DA release displays a different calcium-dependency than terminal DA release: lowering calcium concentration to 0.5 mM prevents axonal DA 303 C214 release but not STD release. Considering that Synaptotagmin (Syt) is the DROSOPHILA NEUROPEPTIDE INDUCES MUSCLE main calcium-sensor for exocytosis and that the different isoforms of Syt CONTRACTION VIA L-LIKE CALCIUM CHANNELS have different calcium-binding affinities, we hypothesize that differences in *Maja Milakovic, Julie Clark, Amanda Cull, A. Joffre Mercier. Dept. of the exocytotic mechanism between the axonal and STD compartments could Biological Sciences, Brock University, St. Catharines be related to differential expression of Syt isoforms. Here we took advantage of a transgenic mouse expressing the EGFP gene driven by the tyrosine DPKQDFMRFamide is the most abundant endogenous FMRFamide- hydroxylase promoter to identify the Syt isoforms expressed by DA neurons. related peptide in Drosophila melanogaster (Schneider & Taghert, PNAS Using single cell RT-PCR, immunochemistry and cell purification by 85:1993-97, 1988). DPKQDFMRFamide enhances neurally-evoked fluorescent activated cell sorting (FACS) we found that freshly-dissociated contractions of larval body wall muscles (Hewes et al., J. Neurosci. 18: 7138- DA neurons as well as DA neurons in culture and in slices express Syt1, Syt4 51, 1998) and enhances excitatory junction potentials (EJPs) (Dunn & and Syt7 but not Syt2 nor Syt9. Interestingly, their localization profile Mercier, Peptides 26:269-76, 2005). At 1 μM, DPKQDFMRFamide showed striking differences: whereas Syt 4 localizes to the STD also induces phasic contractions and increases tonus in body wall muscles of compartment and Syt1 in fine axonal-like processes, Syt7 was found in both unstimulated Drosophila larvae. These effects persist in the presence of 7 compartments. Moreover, the proportion of DA neurons expressing Syt7 mM glutamate, which desensitizes postsynaptic glutamate receptors. Thus, increased with time both in vivo and in culture. Using a siRNA strategy, the effect on tonus cannot be explained by enhanced release of glutamate experiments are currently under way to evaluate the impact of synaptotagmin from synaptic terminals but presumably represents a postsynaptic effect. The isoform downregulation on basal STD DA release in our culture model. Our effect on tonus is abolished in calcium-free saline. Nifedipine, an L-type results are compatible with the hypothesis that differences in calcium calcium channel blocker, reduced DPKQDFMRFamide-induced contraction requirement between axonal and STD DA release can be explained by the in a dose-dependent manner. Nifedipine, at 30 µM, reduced the response to differential localization of Syt isoforms in these two compartments. DPKQDFMRFamide by approximately 90%, suggesting that L-like calcium channels are required for peptide’s postsynaptic effect. The effect of the peptide was not significantly reduced by 0.5 mM amiloride or 1 µM 302 C213 flunarizine, which would not support a role for T-type channels. Supported CELLULAR DISTRIBUTION OF THE NICOTINIC by NSERC. ACETYLCHOLINE RECEPTOR α7 SUBUNIT IN RAT HIPPOCAMPUS John G. Mielke* and Geoffrey A.R. Mealing. Neurobiology Program, 304 C215 Institute for Biological Sciences, National Research Council of Canada, ADULT SPINAL CORD STEM/PROGENITOR CELLS Ottawa DIFFERENTIATE INTO OLIGODENDROCYTES AND SCHWANN CELLS FOLLOWING TRANSPLANTATION INTO THE The density of receptors present on the surface of neurons has become DEMYELINATED SPINAL CORD recognized as an important means to influence synaptic activity. While the Andrea J. Mothe *, Iris Kulbatski, and C.H. Tator. Toronto Western Research movement of the ionotropic glutamate and GABA receptors to and from the Institute, University of Toronto and Toronto Western Hospital, Toronto plasma membrane has attracted significant interest, the nicotinic acetylcholine receptors (nAChRs) have received relatively little attention. Stem/progenitor cells capable of generating new neurons and glia exist in The broad cholinergic innervation of many brain areas indicates that nAChRs specific regions of the adult mammalian CNS, including the spinal cord. modulate network activity, while the α7 homopentamer, which is Stem/progenitor cells derived from the ependymal region of the adult rat widely distributed in the hippocampus, is believed to be important in spinal cord can be cultured in vitro as neurospheres which are multipotential Alzheimer’s disease and schizophrenia. To study cellular distribution of the and can self-renew. Transplantation of these neurospheres has therapeutic α7 subunit, we used organotypic hippocampal slice cultures (OHSCs), potential for spinal cord injury. Following transplantation into the intact or which express the protein in a developmentally regulated manner. Cross- injured rat spinal cord, these neurospheres survive, migrate and integrate linking of surface proteins, differential centrifugation, and cell surface along white matter tracts, and preferentially differentiate into biotinylation all revealed a very limited presence of the α7 subunit at oligodendrocytes. To study the remyelination potential of the the plasma membrane. In contrast, AMPA and GABAA receptor subunits oligodendrocytic progeny of transplanted ependymal region stem/progenitor displayed significant surface expression. To exclude the possibility that the cells, we produced focal demyelination lesions in the spinal cord with unexpected distribution of the α7 subunit was an artifact of the culture ethidium bromide injections. This treatment leaves a population of model, experiments were completed with adult hippocampus, and revealed a demyelinated axons in a glial-free environment that can be used to evaluate similar profile. To monitor distribution of functional α7-containing the remyelinating and differentiation potential of the transplanted cells. We nAChRs, we developed a colourimetric assay that employed α- hypothesized that ependymal region derived stem/progenitor cells bungarotoxin (BGT; a specific α7 nAChR antagonist) conjugated to transplanted into focal demyelination lesions in the rat spinal cord will horseradish peroxidase through biotin-streptavidin. The BGT conjugate was primarily differentiate into oligodendrocytes with remyelinating potential. applied to fixated OHSCs following either non-permeabilizing (surface) or Using a motorized microinjector, focal demyelination lesions were produced permeabilizing (total) conditions, and revealed the majority of α7 by microinjection of 0.1% ethidium bromide into the lateral funiculus of the subunits that formed receptors were at the cell surface. To determine whether spinal cord at level T8. Three days after lesion induction, ependymal region tyrosine phosphorylation could affect α7 subunit trafficking, we next derived stem/progenitors generated from transgenic GFP rats were studied the effect of altering kinase activity. OHSCs were treated with either microinjected into the demyelinated lesion. Cyclosporine A was administered insulin or genistein, and while stimulating phosphorylation had no effect on daily for immunosuppression. We find that GFP expressing stem/progenitor either the cellular distribution of α7 subunits or the level of surface cells survive following transplantation into ethidium bromide-induced focal BGT binding, inhibiting phosphorylation increased the presence of the demyelination lesions in the spinal cord. Following engraftment, subunit at the plasma membrane. Our future work will aim to clarify the stem/progenitor cells primarily differentiate into oligodendrocytes (~70%)

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and few astrocytes (~2%). Neuronal differentiation of transplanted cells was protein into these putative signalling platforms. Here, we describe new data not detected. Interestingly, some GFP positive cells expressed characteristic that depict MBP as a member of the recently described “PIP2-modulin” Schwann cell markers, demonstrating a surprising lineage fate for these cells. proteins [MARCKS, GAP-43, CAP/NAP-22]; thus, MBP’s ability to Therefore, adult stem/progenitor cells derived from the ependymal region of sequester PIP2 may be linked to cellular functions outside its classically the spinal cord primarily differentiate into oligodendrocytic and Schwann accepted role in myelin. These data will be discussed with respect to cellular cell progeny which show a myelinating phenotype following transplantation morphogenesis of oligodendrocytes during maturation, differentiation, and into focal demyelination lesions. These data suggest the therapeutic potential myelinogenesis in health and disease. of spinal cord derived stem/progenitor cells for remyelination.

307 C218 305 C216 THE FUNCTIONAL SIGNIFICANCE OF SEIZURE-INDUCED GAP CALCIUM CHANNEL SUB-TYPES INVOLVED IN LONG-TERM JUNCTION-BASED SYNCHRONOUS ACTIVITY AND GENE ADAPTATION OF CRAYFISH MOTOR NEURONS EXPRESSION IN THE ISOLATED MOUSE HIPPOCAMPUS Megan Mottershead* & A. Joffre Mercier. Brock University St. Catharines Shanthini Mylvaganam, Miron Derchensky, Chipping Wu, Mandy Mamani, James Eubanks, Liang Zhang, Peter Carlen and Michael Poulter Motor neurons can be characterized as tonic (highly active) or phasic (largely inactive). Tonic motoneurons typically have low output synapses There are several reviews implicating gap junctions in epileptogenesis with long filiform terminals, and phasic motoneurons typically have high (Dudek et al., 1986; Jeffreys, 1995; Dudek et al., 1998; Carlen et al., 2000; output synapses with large varicose terminals (Atwood & Wojtowicz, Perez Velazquez & Carlen, 2000; Dudek, 2002; Traub et al., 2004). Internat. Rev. Neurobiol. 38:275-362, 1986). Increasing the electrical activity Compelling evidence now exists that direct cell-to-cell communication is up of phasic axons over 3-14 days changes synaptic properties and nerve regulated in neuronal hyperactivity and seizures. It is hypothesized that terminal morphology to resemble tonic neurons (Lnenicka et al., J. Neurosci. seizure-induced increased synchronous activity could be due to several 6:2252-58, 1986). These changes, referred to as long-term adaptation, require factors including enhanced gap junctional channel function, increased gap extracellular calcium and are correlated with reduced calcium influx through junctional expression, or both. Studies have shown that glial gap junctions P-type calcium channels in the neuronal cell body (Hong & Lnenicka, J. also play an important role in epileptogenesis. Increased Cx43 mRNA, Neurophysiol. 77:76-85, 1997). The present study sought to characterize the presumably in glia and not in neurons, was observed in peritumoral brain calcium channel types responsible for the reduced transmitter release during tissue surgically removed from patients whom had seizures compared to long-term adaptation of phasic axons. Selective calcium channel blockers those without seizures (Naus et al., 1991; Aronica et al. 2001). We used were used to determine the relative contribution of calcium channel subtypes different seizure models to test the above hypothesis. The intact hippocampi to excitatory junctional potentials (EJPs) in crayfish abdominal extensor isolated from 15-day-old mice was separated into dentate gyrus and CA muscles. Crayfish axons were stimulated for 1-2 hours per day for 3 days, portion and were made epileptic from chronic bicuculline (BMI, a GABAA and EJPs were recorded 1-3 days afterward. EJPs were not altered by the N- antogonist) exposure for 6 hours or treated with 100uM Cobalt chloride for type channel blocker, ω-Conotoxin GVI A but were reduced by 60% by 1 hour. In the case of BMI model, extra cellular field recordings for up to one the P-type blocker, ω-Agatoxin IVA. Thus, 60% of transmitter release hour, demonstrated recurrent epileptiform activity, which is blocked by the appears to be associated with P-type channels, and 40% is associated with gap junctional blocker, carbenoxolone. The cobalt-induced epileptiform calcium channels that are neither P-type nor N-type. Long-term adaptation activity was blocked by phenytoin. After washing off the BMI and cobalt did not alter the sensitivity of the EJP to either channel blocker. Thus, the with ACSF, the changes in cellular mRNA expression of connexins and reduction in transmitter release does not involve a redistribution in the pannexins were analyzed using quantitative Real time PCR method (QRT- percentage of calcium channel sub-types but may result from equal changes PCR). The expression of 90-110 bp amplicons from several connexins in calcium influx through P-type and non-P/non-N type calcium channels in (Cxn26, Cx30, Cxn32, Cxn36, Cxn40, Cxn43, Cxn45 and Cxn47) and the synaptic terminals. Supported by NSERC. pannexins (Pxn1, Pxn2 and Pxn3) were analyzed. The results indicated up regulation of mRNAs of Pxn1, Pxn2, and Cxn43 in the CA portion of the cobalt-treated hippocampi. Pannexins, Pxn1 and Pxn2, were increased by 306 C217 about 1 fold and Cxn43 expression went up by 2 folds. However no changes MBP AS A “PIP2-MODULIN” PROTEIN: NEW BIOLOGICAL were observed in the dentate gyrus. In the BMI model, no significant change FUNCTION FOR AN OLD CNS PROTEIN. was observed in the CA portion of the hippocampi, however, the expressions Abdiwahab A. Musse1, Trevor Ormiston1, Wen Gao2, Joan M. Boggs2, & of Cxn30 and Cxn43 were elevated > 2 fold in the DG region. When the level George Harauz1. 1Department of Molecular and Cellular Biology, of expression between the connexins and Pannexins were compared in the University of Guelph, Guelph. 2Department of Structural Biology and CA and DG portions of the control hippocampi, the following order was Biochemistry, Research Institute, Hospital for Sick Children, Toronto observed: Cxn43 ~ Cxn30 > Px2 > Px1 ~ Cxn32 > Cxn26 > Cxn36 ~ Cxn47 ~ Cxn45 > Cxn40. Comparison of the correl The classically accepted biological function of myelin basic protein (MBP), one of the major protein components of myelin in central nervous system (CNS), is the maintenance of myelin sheath compaction. Owing to its 308 C219 extreme net positive charge, MBP serves as an adhesive molecule in CNS NEURONAL AND GLIAL CONNEXINS, ELECTRCIAL SYNAPSES myelin sheaths, bringing together the two apposing faces of the cytoplasmic AND GAP JUNCTION-ASSOCIATED PROTEINS IN THE CNS leaflets of the cell membrane processes of myelinating cells, JI Nagy, X Li, C Olson, B Lynn and JE Rash. Department of Physiology, oligodendrocytes (OL), to effect myelin compaction around axons. During Faculty of Medicine, University of Manitoba, 730 William Avenue, Winnipeg, the past years, it has been shown that MBP binds and polymerizes/bundles and Colorado State University, Ft. Collins, CO, USA actin and tubulin, in a manner modulated by post-translational modifications. We have also shown MBP to interact with Ca2+-calmodulin with relatively Twelve connexins (Cx) form gap junctions between various cell types in strong affinity, and that this interaction regulates the MBP’s membrane the adult mammalian CNS: astrocytes express C26, Cx30 and Cx43; association, and ability to polymerize actin in the presence and absence of oligodendrocytes express Cx29, Cx32 and Cx47; neurons express Cx36, lipids. Moreover, we have shown MBP to associate with lipid rafts, and that Cx45, Cx50 and Cx57; vascular cells express Cx37, Cx40 and Cx45. We different post-translational modifications influence the partitioning of this used immunofluorescence, freeze-fracture replica immunogold labelling

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(FRIL) and molecular approaches to study the distribution, cellular Neural coding stems from transduction of graded synaptic input into all- localization and protein interaction partners of these connexins. Among glial or-none spikes. Understanding this transduction mechanism is crucial for cells, gap junctions composed of multiple connexins exhibit regional and deciphering precisely what information is encoded by a spike train. Using cellular heterogeneity, and interdependency of connexin trafficking and computational modeling coupled with electrophysiological experiments, we coupling profiles. Glial gap junctions are found to be associated with a show how spinal sensory neurons with distinct transduction properties variety of regulatory and scaffolding proteins, including ZO-1, ZONAB and encode either the integral (running sum) or derivative (rate of change) of MUPP1. The important functional role of gap junctions forming the pan-glial their input. Spike generating dynamics differed fundamentally between cell syncytium in CNS homeostasis is indicated by reports of neural pathology types: integrators switched to repetitive spiking when sufficiently strong and physiological impairments in glial connexin knockout mice, and CNS stimulation destabilized the system, whereas differentiators maintained disorders in humans with glial connexin mutations. Among neurons, gap stability and spiked only upon abrupt changes in stimulus intensity. junctions composed of Cx36 form electrical synapses that are widely Generating spikes through the former mechanism allowed stimulus intensity distributed throughout adult brain and spinal cord, and those composed of to be encoded with firing rate, whereas generating spikes through the latter Cx50 and Cx57 occur exclusively between neurons in retina. In addition, co- allowed changes in stimulus intensity to be encoded with spike times. localization of Cx36 with markers of nerve terminals in some brain regions Simulations identified direction of subthreshold current (i.e. whether current indicate the presence of gap junctions at terminals forming mixed synapses active at voltages below spike threshold was depolarizing or hyperpolarizing) (chemical and electrical). Gap junctional and direct molecular association of to be a critical determinant of the spike generating dynamics. In turn, Cx36 with the scaffolding proteins ZO-1, ZO-2 and MUPP1 was experiments demonstrated that integrators and differentiators expressed demonstrated by analyses of in vivo and in vitro systems. Electrical coupling either a subthreshold inward (calcium) or outward (potassium) current, between neurons is known to generate synchrony of subthreshold membrane respectively, that was necessary and sufficient to explain the spike generating oscillations and to promote synchronous low and high-frequency rhythmic dynamics. By mediating positive feedback control of the subthreshold oscillations in neuronal networks. Such synchronous rhythmic oscillations voltage trajectory, inward current sustains depolarization and causes the occur in nearly every part of the brain. It is widely considered that neuron to spike on the basis of its integrated stimulus waveform; conversely, synchronous oscillations serve as a mechanism to “bind” the activity of outward current mediates negative feedback, truncating depolarization and distributed neuronal networks, and that this synchrony-mediated binding in causing the neuron to spike on the basis of its differentiated stimulus the CNS underlies a wide range of information processing related to memory waveform. The causal link between direction of subthreshold current and formation and retrieval, sensory perception, motor control, attention and implementation of fundamental operations (integration and differentiation) is plasticity. Thus, electrical synapses formed by neuronal gap junctions appear rigorously demonstrated through dynamical systems analysis and likely to play a key and indispensable role in neural network properties and constitutes a universal calculus for neural computation. cognitive function. Supported by grants from the CIHR to JIN, and by NIH NS44010 and NS44395 to JER. 311 C222 BDNF-DEPENDENT MODIFICATION OF NMDA RECEPTOR 309 C220 SIGNALING PATHWAYS INVOLVED IN LONG-TERM FEED-FORWARD INHIBITION DECREASES EPSPAMPLITUDE POTENTIATION IN HIPPOCAMPAL AREA CA1 Robinson K.N., Fredin, E.L., Hryciw T., Meakin, S.O.. Graduate Program Jake Ormond and Melanie Woodin. Department of Cell and Systems Biology, in Neuroscience, University of Western Ontario Microbiology and University of Toronto Immunology, University of Western Ontario Robarts Research Institute, Cell Biology Group Long-term potentiation (LTP) of glutamatergic transmission in the hippocampus is widely accepted as a cellular substrate for learning and Long-term potentiation (LTP), a long lasting enhancement of synaptic memory in the brain. In area CA1 of the hippocampus, both high frequency response following neural stimulation, is a proposed cellular correlate of presynaptic stimulation and low frequency correlated pre- and postsynaptic memory. The proteins mediating this phenomenon in post-synaptic spiking can induce LTP, measured as an increase in the amplitude of membranes include the NMDA receptor (NMDAR) and the receptor tyrosine excitatory postsynaptic potentials (EPSPs). However, stimulation of the kinase, TrkB. Activation of TrkB by BDNF increases the activity of NMDAR presynaptic inputs also activates feed-forward inhibitory circuits onto the resulting in enhanced LTP through mechanisms that are currently being same postsynaptic CA1 pyramidal neurons. The delay separating the investigated. We propose that differential interactions between a brain- postsynaptic EPSP from the inhibitory postsynaptic potential (IPSP) is only specific protein, RasGrf1, and NMDAR or TrkB may modify downstream 1.9 ms, suggesting that the measured peak of the EPSP may in fact be the signaling pathways thus altering LTP. RasGrf1 interacts directly with the peak of a mixed EPSP/IPSP. Using whole-cell recordings from rat NR2B subunit of NMDAR resulting in increased phosphorylation of p38- hippocampal slices, we have investigated this hypothesis. By manipulating MAPkinase and increased long-term depression (LTD), a long-lasting the strength of GABAergic inhibition, achieved simply by hyperpolarizing or decrease in synaptic response. RasGrf1 also interacts with and is depolarizing the membrane potential relative to the reversal potential for phosphorylated by TrkB in transfected cells resulting in morphological GABAergic currents, we show that feed-forward inhibition greatly decreases changes such as increased neurite outgrowth in TrkB-B5 cells. Preliminary EPSP amplitude. This suggests that GABAergic plasticity is another data indicates that BDNF stimulation of adult mouse (P30) cortical slices mechanism whereby the strength of glutamatergic transmission could be results in the loss of interaction between NMDA/KCL-stimulated NR2B and altered, and therefore, might play an important role in learning and memory. RasGrf1. This loss of interaction is also associated with a decrease in p38- MAPkinase activation and a corresponding increase in Erk activation. Could the loss of interaction between NR2B and RasGrf1, due to competitive 310 C221 interaction with TrkB, decrease activation of pathways generating LTD, DYNAMICAL MECHANISMS OF NEURAL CODING AND THEIR resulting in increased LTP? Continuing research aims to further clarify the BIOPHYSICAL BASIS nature of the neuronal interaction between TrkB and RasGrf1 and to Steven A. Prescott (*1), Terrence J. Sejnowski (1,2), and Yves De Koninck determine whether, in addition to modifying NMDAR signaling, TrkB and (3). 1. Computational Neurobiology Laboratory, Howard Hughes Medical RasGrf1 could also strengthen LTP by promoting morphological changes Institute, Salk Institute for Biological Studies, La Jolla, USA. 2. Division of such as the formation of neuronal processes or dendritic spines. Biological Sciences, University of California, San Diego, La Jolla, USA. 3. Division de Neurobiologie Cellulaire, Centre de Recherche Université Laval Robert-Giffard, Québec, Canada

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312 C223 phosphorylation at serines 199/202 and serine 214. Notably, the PKA SPREADING DEPRESSION IN AN INSECT GANGLION inhibitor Rp-cAMPS, reverses tau phosphorylation at serine 214 but not at Corinne I. Rodgers*, John D. LaBrie, and R. Meldrum Robertson serines 199-202. These data are the first in vitro demonstrations showing that activation of the D1 dopamine receptor could have profound influence on the Spreading depression (SD) in mammalian cortical tissue is closely cytoskeletal remodeling of neurons, for which Cdk5 likely play a pivotal associated with several important pathologies including stroke, seizures and role. migraine. The mechanisms underlying SD in its various forms are still incompletely understood. Here we describe an SD-like event in an insect model system. Using K+-sensitive microelectrodes, we measured 314 C225 extracellular K+ concentration ([K+]o) in the neuropile of the locust THE EFFECT OF CONNEXIN 43 MIMETIC PEPTIDES ON ventilatory central pattern generator (CPG) while monitoring CPG output NETWORK ACTIVITY IN ORGANOTYPIC RAT HIPPOCAMPAL electromyographically from muscle 161 in the second abdominal segment. SLICES We investigated the role of K+ in failure of neural circuit function induced *Marina Samoilova1, Kirsten Wentland1, Yana Adamchik1, Alexander A. by various stressors. An abrupt rise in [K+]o was reliably associated with Velumian2,3,4,6 and Peter L. Carlen1,4,5. Divisions of 1Fundumental heat-induced failure of the ventilatory motor pattern, which occurred in Neurobiology and 2Genetics and Development, Toronto Western Research 100% of preparations. The rise in [K+]o reached a plateau of ~52mM on Institute; 3Krembil Neuroscience Center, Toronto Western Hospital, average. [K+]o was restored to normal baseline levels if heat was removed University Health Network; Departments of 4Physiology, 5Medicine and this was associated with recovery of ventilatory motor patterning. The (Neurology) and 6Surgery, University of Toronto [K+]o event was reliably triggered by several cellular stressors in addition to hyperthermia, including anoxia, ATP depletion using sodium azide, Using two connexin mimetic peptides (CMPs), short synthetic peptides artificially increased [K+]o within the ganglion, and Na+/K+ ATPase corresponding to selected sequences in the two different extracellular loops dysfunction induced by ouabain. In many preparations failure of rhythmic of connexin 43 (mainly expressed in astrocytes in contrast to favored bursting preceded a burst of tonic electrical activity that occurred on the neuronal expression of connexin 36), the possible role of glial connexin- rising phase of the [K+]o increase. Repetitive [K+]o surges were triggered dependent processes in the network activity was studied in cultured by ouabain in a concentration-dependent manner. 10-4M ouabain bath organotypic rat hippocampal slices. The CMPs used were: Gap 27 (amino application induced cycles of [K+]o increase and decrease that occurred acid residues 201-211 of the rat connexin 43, SRPTEKTIFII) and SLS- every 3-5 minutes and were associated with failure and recovery of the motor peptide (amino acid residues 180-195, SLSAVYTCKRDPCPHQ). The pattern. We found that the [K+]o disturbance propagates from its origin at a effects of these CMPs were compared to those induced by carbenoxolone rate of about 2 mm/min. We also measured ATP levels in the metathoracic (CBN), a widely used gap junctional blocker with no preferential activity ganglion and found no correlation between ATP levels and initiation of [K+]o toward cell-specific (neuron vs. glia) types of gap junctions composed of surges by different stressors. [K+]o surges were not dependent on electrical different connexin isoforms. Neither CBN, nor CMPs had significant effects activity, though reduction of electrical activity with TTX delays their on synaptic transmission in the CA1 area of the hippocampus. The peak occurrence. Blockage of K+ channels with TEA significantly reduces the amplitude of population spike was 4.11±0.47 (n=18), 6.19±3.28 (n=5), amplitude of the surge in [K+]o. We conclude that these events represent 4.74±0.72 (n=7) and 5.53±1.17 (n=12) mV in control conditions and after spreading depression, and that in this model system such activity can be treatment with CBN, Gap 27 and SLS-peptide, respectively. At the same interpreted as an adaptive mechanism to shut down neural function and time, CBN strongly inhibited different manifestations of epileptiform conserve energy in response to stress. network activity including the primary afterdischarge evoked by tetanic stimulation. In contrast, the CMPs suppressed only the spontaneous recurrent epileptiform activity without apparent effects on evoked responses. Notably, 313 C224 the CMPs required much longer treatment time (>10 hours) to exert marked DOPAMINE RECEPTOR AND MICROTUBULE-ASSOCIATED effects. The ability of the compounds studied to suppress seizure-like PROTEIN FUNCTIONS: A ROLE FOR THE CYCLIN-DEPENDENT activity positively correlated with the degree of gap junctional coupling KINASE 5 measured by the extent of the fluorescence recovery after photobleaching Manon LeBel* and Michel Cyr. Université du Québec à Trois -Rivières (FRAP). The differential effects of CBN and CMPs could be due to differences in their target connexin isoforms, reflecting cell type-specific An increasing number of evidence demonstrates that drugs affecting actions. Thus, stronger FRAP inhibition induced by CBN compared to CMPs dopamine levels in the brain can induce cytoskeletal modifications and D1 could result from its non-selective inhibition of both neuronal (connexin 36) dopamine receptors likely play a pivotal role in this process. These evolving and glial (connexin 43) gap junctions, while Gap 27 and SLS-peptide changes may impact striatal synaptic plasticity as cytoskeletal constituents inhibited FRAP only “partially” due to their possible “selective” effect on are involved in the maintenance of dendritic processes and that any changes glial gap junctions. Despite some technical challenges, the CMPs are a in their stability could affect major cellular compartments of neurons like promising pharmacological tool to study isoform-specific connexin- dendrites, spines and synapses. Our recent data suggest that activation of the dependent processes in the CNS. Supported by Canadian Institutes for D1 dopamine receptor could lead to enhanced phosphorylation of the Health Research, Hospital for Sick Children Research Foundation and microtubule-associated protein tau, normally involved in the microtubule Epilepsy Canada. stabilization. The purpose of the present study is to investigate the role of D1 receptor signaling constituents in this process. By using selective antibodies that recognize specific phosphorylation sites of tau, we show that in SK-N- 315 C226 MC cells, endogenously expressing D1 receptors, escalating doses of the D1 MODULATION OF P2X3 AND P2X2/3 SENSORY receptor agonist SKF 38393 (1 to 100 μM) increase the levels of tau PURINOCEPTORS BY PHOSPHOINOSITIDES phosphorylation at serines 199/202 (Cdk5 site) and serine 214 (PKA site). Gary Mo, Louis-Philippe Bernier, Anne-Julie Chabot-Doré, Dominique Blais These effects are likely due to the activation of D1 receptors since they can and Philippe Séguéla. Montreal Neurological Institute and McGill Centre for be reversed by a 30 minutes pre-treatment with 100 µM of the D1 receptor Research on Pain, Dept. Neurology & Neurosurgery, McGill University, antagonist SCH 23390. We also show that Cdk5 play a central role in tau Montreal phosphorylation induced by D1 receptor activation as roscovitine and calpeptine, a direct and an indirect Cdk5 inhibitors, respectively, reverse tau The phospholipids phosphatidylinositol 4,5-bisphosphate (PIP2) and phosphatidylinositol 3,4,5-trisphosphate (PIP3) are involved in many cellular

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processes such as membrane trafficking and cell motility. They have also Ca2+ spikes associated with Ca2+ entry into postsynaptic neurons, could been shown to modulate several types of ion channels. We report here significantly influence synaptic transmission and gate the ascending evidence that these phosphoinositides are able to modulate the function of information passing through the thalamus. ATP-gated P2X receptor-channels expressed in primary sensory neurons and in heterologous systems. In dissociated rat DRG neurons, 2-3 hours incubation with the PI3K/PI4K inhibitor wortmannin at 35 microM induced 317 C228 a dramatic decrease (64%) in the amplitude of alpha,beta-meATP-evoked THE ROLE OF C2A AND C2B DOMAINS OF SYNAPTOTAGMIN I P2X3 receptor-mediated currents. Intracellular application of PIP2 was able AT A SPECIFIED SYNAPSE DURING MEMORY to fully reverse the inhibition induced by wortmannin while incubation for 2- CONSOLIDATION 3 hours with wortmannin at 100 nM (a selective PI3K inhibitor at this Anthony Senzel & Zhong-Ping Feng. Department of Physiology, Faculty of concentration) produced no significant effect on P2X3 currents. Both in Medicine, University of Toronto, Toronto Xenopus oocytes and in HEK 293 cells transiently transfected with rat P2X3, 35 microM wortmannin incubation induced a significant decrease in the rate We are a product of what we have learned in our histories and, in such, of receptor recovery. The modulation of P2X2/3 heteromeric purinoceptors of what we are able to recall in relation to that. Much work has been done in by phospholipids was also analyzed in the Xenopus oocyte expression recent years to understand the molecular mechanisms, including necessary system. Slowly-desensitizing P2X2/3 receptor-mediated currents were transcription factors and associated pathways, in memory formation. Despite decreased by 56% after a 2-3 hours incubation in wortmannin 35 microM, these advances, much data has yet to be obtained in regards to what is and by 39 and 29% after incubation with wortmannin 100 nM and selective occurring at the level of the synapse. Questions remain as to whether there is PI3K inhibitor LY294002 35 microM, respectively. The P2X2/3 current formation of new synapses or a strengthening of old ones, during the amplitude decrease induced by wortmannin could be partially reversed by acquisition of a new memory. In vitro work previously conducted in our lab application of PIP2 or PIP3, indicating that assembly of P2X2 and P2X3 has demonstrated the putative calcium sensor, synaptotagmin I, is critical for subunits confers to the heteromeric complex a sensitivity to both the formation of presynaptic structures which leads to functional nascent phospholipids. In summary, our data demonstrate a novel mode of functional synapses. This effect is mediated through a Ca2+ binding motif at the C2A regulation of the homomeric P2X3 and heteromeric P2X2/3 subtypes of ATP domain. By introducing a synthesized HIV1-TAT conjugated C2A peptide receptors by the levels of PIP2 and PIP3 in the plasma membrane of DRG specific to the Ca2+ binding region acting in a dominant negative manner, neurons. The molecular basis of these P2X-phosphoinositides modulatory synaptic vesicle aggregation and synapse formation is prevented. The interactions is currently under investigation. Supported by CIHR and objective of this study thus is to investigate the contribution of new synapses NSERC-IPS (AstraZeneca R&D Montreal). in long-term memory formation in a well established operantly conditioned learning model (Lukowiak et al., 1996), using the C2A peptide as a tool. Specifically, the giant pond snails Lymnaea stagnalis were placed in a 316 C227 hypoxic environment, in which the snails were driven to breathe via a LOW-THRESHOLD SPIKES-DEPENDENT EXTRACELLULAR respiratory orifice -the pneumostome at the water surface. The number of CALCIUM DEPLETION CONTROLS SYNAPTIC SENSITIVITY OF pneumostome openings and total breathing time were measured. The snails THALAMOCORTICAL NEURONS TO LEMNISCAL were then conditioned by applying a tactile stimulus to the pneumostome STIMULATION contingent upon its opening, and following this training regime; the snails Seigneur, Josée* and Timofeev, Igor. Centre de recherche Université Laval effectively learned to avoid this behaviour. After 24 hours, the memory is Robert-Giffard, Québec tested by measuring total breathing time and pneumostome openings and comparing to the results obtained prior to training. Injection of the C2A Thalamus is the main gateway of cerebral cortex. Extracellular unit peptide 1-1.5 hrs after the final training session prevented the snail from recordings demonstrated a preferential burst firing of TC neurons during forming a memory. Snails injected with a C2A peptide mutated (C2A-mut) slow-wave sleep and tonic firing during both REM sleep and waking states. to prevent Ca2+ binding behaved similar to those previously obtained for During tonic firing mode EPSPs arising from activities in ascending controls in which total breathing time significantly decreased after training. pathways easily drive action potentials sending signals to cerebral cortex. This group also displays no change in number of pneumostome openings During sleep, unitary prethalamic EPSPs either do not elicit neuronal firing from the final training session as compared to the memory test. Taken or elicit spike burst that is followed by neuronal silence. Burst firing is together the results demonstrate a necessary involvement of the newly mediated by low-threshold Ca2+ spikes (LTS). We hypothesize that Ca2+ formed functional synapses in long term memory consolidation. influx during LTS results in a local Ca2+ depletion from extracellular space, which affected sensitivity of postsynaptic neuron to presynaptic inputs and contributes to the generation of neuronal silence that follows the burst. The 318 C229 objective of this study was to investigate the modulation of mediator release THE ROLE OF CALCINEURIN, CYTOSKELETON AND CALPAIN probability caused by postsynaptic Ca2+ spikes. We test our hypothesis by IN LOW FREQUENCY DEPRESSION OF SYNAPTIC recording responses of thalamocortical neuron from VPL nucleus in rat brain TRANSMISSION +C339 slices maintained in vitro during low intensity stimulation of the medial Silverman-Gavrila, LB#, Charlton, MP. Department of Physiology, Faculty lemniscus. LTS was elicited with hyperpolarizing current pulses. The of Medicine, University of Toronto lemniscal stimulation intensity was set to obtain minimal EPSPs amplitude and some failures. Simultaneously, Ca2+ ion-sensitive electrode was placed Transmitter release at crayfish leg extensor NMJ phasic synapses juxtacellularly of the recorded neurons to measure Ca2+ depletion during declines by over 50% in 60 min at 0.2 Hz stimulation. This low-frequency LTS. Minimal lemniscal stimulation induces 0.31 ± 0.06 mV EPSPs with a depression (LFD) is regulated by protein phosphorylation by PKA and PKC failure rate of 34.4 ± 22.2 % in control (n=6). When lemniscal stimuli were and dephosphorylation by proteinphosphatases 1, 2A and 2B (calcineurin) applied during and/or immediately after LTS the failure rate of synaptic (Silverman-Gavrila et al., 2005, J. Neuroscience). The permeant calcineurin responses increased reaching 78.6 ± 22.4 %. Lower amplitude LTS, the LTS inhibitors FK-506 or autoinhibitory peptide abolished LFD. To determine if that did not lead to the generation of action potentials increased failure rates the site of action of calcineurin is pre or/and postsynaptic we pressure to a lesser extent. Failure rate level was recovered to control values on injected impermeant calcineurin autoinhibitory peptide into presynaptic average 225 ± 45 ms after the maximum of LTS. Extracellular Ca2+ axons or postsynaptic muscle cells and measured the amplitude of the depletion followed LTS with delays of several milliseconds and paralleled intracellularly recorded excitatory postsynaptic potential (EPSP) evoked by modulation of failure rates. Our findings thus indicate that the generation of

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stimulating the phasic axons at 0.2 Hz. LFD was decreased only when spinal galanin produces an anti-nociceptive effect. Galanin is thought to calcineurin was inhibited in the presynaptic nerve terminal. The drugs have produce these effects via activation of GalR1. Galanin is also thought to no postsynaptic effects since FK-506 or permeant peptide did not affect produce pro-nociceptive effects via activation of pre-synaptic GalR2 amplitude distribution of spontaneous miniature EPSPs; therefore they target receptors on primary afferents. However, the physiological role of galanin in presynaptic calcineurin, the activity of which is necessary for LFD spinal nociception is still relatively elusive. Using whole cell recordings, in (Silverman-Gavrila and Charlton, J. Neuroscience, submitted). Neither drug both delay (excitatory) and tonic (inhibitory) and the GalR2 specific agonist affected high frequency depression caused by 20 Hz stimulation. Since Ca2+ ARM1896, (500nM) or the Gal1/2 specific agonist M961 (500nM) in the buffering by injected BAPTA-based Ca2+ indicators or EGTA-AM treatment presence of GalR1 antagonist (M871, 2.5 microM), we investigated the did not inhibit LFD, calcineurin activation may occur very close to Ca2+ actions of galanin in rat substantia gelatinosa. The most conspicuous effects channels where a large Ca2+ signal is available. Alternatively, a limited included 1) a GalR1-mediated increase in outwardly and/or inwardly proteolysis of calcineurin by Ca2+-dependent protease calpain might be rectifying K+ conductances in putative excitatory, delay neurons 2) a GalR2- involved in calcineurin activation during LFD. Calpain is present at crayfish mediated reduction in frequency and amplitude of spontaneous EPSC’s in neuromuscular junction as shown by immunostaining and Western blot delay cells and 3) a GalR2 agonist decrease in the excitability of tonic analysis. Pharmacological inhibition of calpain with calpain inhibitor I and inhibitory cells. The first two effects would be consistent with an anti- PD145305 blocked LFD, while the inactive negative control compound nociceptive effect whereas the third may be pro-nociceptive. Thus, some PD150606 did not affect LFD. A feed-back regulatory mechanism of LFD aspects of our results fit with the notion that GalR1 activation produces possibly involves TRPM7 ion channel, a calpain substrate present at the analgesia whilst GalR2 activation may produce hyperalgesia (see Liu & crayfish NMJ. To examine changes in phosphoproteins during LFD, we Hokfelt, TIPs 23:468-474, 2002). Supported by CIHR. removed motor axons and nerve terminals after the induction of LFD or treatment with various phosphorylation regulators, extracted their proteins, separated them by SDS-PAGE, and stained them with phosphospecific stains 321 D203 ProQ-Diamond/SYPRO Ruby to identify bands for analysis by mass VASCULATURE GUIDES MIGRATING NEUROBLASTS IN THE spectrometry. Actin and tubulin phosphorylation was decreased during LFD. ADULT FOREBRAIN Western-blot analysis and immunostaining showed calcineurin, actin and Marina Snapyan*, Claude Gravel and Armen Saghatelyan. Centre de tubulin at presynaptic axons and terminals. The involvement of cytoskeletal recherche Universite Laval Robert-Giffard, Quebec elements in LFD was proved pharmacologically. The anti-actin drug cytochalasin and the microtubule stabilizer taxol inhibited LFD, while the The adult subventricular zone (SVZ) – olfactory bulb (OB) system is a tubulin depolymerizing drug nocodazole accelerated LFD with no post- unique region in the mammalian forebrain where massive neuronal migration synaptic effects. In conclusion, dephosphorylation of presynaptic actin and is observed. First, neuroblasts migrate tangentially in the rostral migratory tubulin by calcineurin possibly activated by calpain may regulate LFD. stream (RMS), a long and intricate migratory pathway, and then radially in the OB. Despite extensive investigations of the molecular signals involved in these two different migratory modes, it is still unknown how neuronal 319 D201 precursors travel through complex brain territories to reach OB, and what EFFECT OF CHOLESTEROL DEPLETION ON CEREBELLAR mechanisms confine them within the migratory pathways. We recently SYNAPTIC TRANSMISSION uncovered a completely unexpected organization of blood vessels in the Alexander J. Smith, Milton P. Charlton. Department of Physiology, migratory stream in the adult forebrain that might be related to the migratory University of Toronto process. While blood vessels are randomly organized in most brain regions, they parallel migrating stream in the RMS and essentially all neuroblasts Alterations in membrane cholesterol content are associated with migrate in their close proximity. Interestingly, in the OB core where endogenous modulation of synaptic strength and also occur in a number of neuroblasts have to detach from one another to start migrating individually neurodegenerative conditions. We have investigated the effects of reducing and radially to the different bulbar layers, many blood vessels are now membrane cholesterol content on synaptic transmission between presynaptic oriented perpendicular to the tangentially migrating neuroblasts (i.e. parallel granule cells and postsynaptic Purkinje cells in dissociated cerebellar to the radialy migrating cells). The cells that exit from RMS and start their cultures. The cholesterol extracting agent methyl-β-cyclodextrin radial migration into the bulbar layers do so along these perpendicularly (mβCD, 5mM) caused a significant decrease in the amplitude of oriented blood vessels. In the search for the molecular mechanism of evoked EPSCs measured at the Purkinje cell soma. Current clamp vasculature-guided migration of neuronal precursors in the adult brain, we measurements of the somatic granule cell action potential indicated that it discovered that endothelial cells of blood vessels synthesize BDNF which is was unaffected by cholesterol extraction under these conditions. The mean released to the extracellular space and trapped by astrocytic processes amplitude of miniature EPSCs was unchanged by mβCD treatment and ensheathing migrating neuroblasts. Stereotaxic injection of BDNF into the their frequency was increased approximately 10 fold. The increase in mEPSC striatum, a region outside the migratory pathway of these neuronal frequency occurred in both Ca2+ containing and Ca2+ free extracellular precursors, de-routes the cells from their normal migratory stream into this medium. Results suggest that cholesterol extraction reduces synaptic strength area. Altogether, our data demonstrates that blood vessels define the by reducing quantal content, but a reduction in vesicle release probability or migratory stream in the adult forebrain, and guide migrating neuroblasts presynaptic excitability is unlikely to account for this observation. toward and into the OB via a local action of BDNF.

320 D202 322 D204 ELECTROPHYSIOLOGICAL STUDIES OF THE EFFECT OF IDENTIFICATION AND CHARACTERIZATION OF AN GALANIN IN RAT SUBSTANIA GELATINOSA INVERTEBRATE T-TYPE CALCIUM CHANNEL Kwai A Alier(1), Ulla Sollenberg(2), Ülo Langel(2) and Peter A. Smith(1). A. Senatore‡, X. Huang‡, A.B. Smit# and J.D. Spafford‡. #Research Institute (1) Centre for Neuroscience and Dept. Pharmacology, University of Alberta, Neurosciences, Vrije Universiteit Amsterdam ‡Dept. of Biology, U. of Edmonton and (2) Dept. Neurochemistry Stockholm University, Stockholm, Waterloo Sweden T-type calcium channels are active at the resting potential, inactivate Galanin is a 29 amino acid peptide expressed in the dorsal root ganglia rapidly and bear small single-channel conductances. T-types generate low- and spinal dorsal horn interneurons. Behavioral studies have shown that threshold calcium spikes and influence action potential patterns, participate

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in cardiac pacemaker activity, regulate smooth muscle tone, hormone member of LAP (leucine-rich repeats and PDZ domains) family, has been secretion, and the acrosome reaction in sperm. T-Type channels are shown to regulate the localization of synaptic vesicles at neuromuscular implicated in human pathologies such as cardiac hypertrophy, childhood junctions in Drosophila. We have shown that Scribble is developmentally absence epilepsy, cancer, and pain. Our lab has begun analyses of a neuronal, regulated in the brain, with dramatically greater expression in P1 whole 2683 amino acid T-type channel from the pond snail Lymnaea stagnalis. mouse brains compared to adult brains, suggesting a role for Scribble in early Comparative analyses of LCav3 to its three human orthologs (Cav3.1-3.1) synaptic development. Indeed, Scribble is expressed at presynaptic provide a unique prospective for understanding T-type channel functions and compartments and colocalizes with both -catenin and related pathologies. Les canaux de type T sont actifs au potentiel de repos, synaptophysin in cultured hippocampal neurons. Furthermore, Scribble can s’inactivent rapidement et soutiennent de petites conductances d’un canal be co-immunoprecipitaed with -catenin, but this interaction has unique. Les types T génèrent des pics de calcium de bas seuil et influencent been proved to be indirect using in vitro transcription-translation assays. We les patrons de potentiel d'action, participent à l'activité de stimulation are currently using an siRNA approach to determine the functional role of cardiaque, régularisent le tonus du muscle lisse, la sécrétion hormonale et la Scribble in hippocampal neurons. Using three siRNA sequences, we show réaction de l’acrosome dans le sperme. Les canaux de type T sont impliqués that depletion of endogenous Scribble results in the dispersion of vesicles dans des pathologies humaines comprenant l'hypertrophie cardiaque, along the axon, and phenocopies that of -catenin ablation. We l'épilepsie avec absences de l’enfance, le cancer, et la douleur. Notre therefore conclude that Scribble may function downstream of - laboratoire a débuté la caractérisation structurale et fonctionnelle d’un canal catenin to recruit synaptic vesicles to developing presynaptic compartments. T neuronal de 2683 acides aminés provenant de l’escargot d'étang, Lymnaea stagnalis. Les analyses comparatives de LCav3 à ses trois orthologues humains (Cav3.1-3.1) fournissent une prospective unique vers la 325 D207 compréhension des fonctions des canaux T et les pathologies y étant reliées. TRANSLOCATION OF TRPC5 CHANNELS CONTRIBUTES TO CHOLINERGIC-INDCUED PLATEAU POTENTIALS Chao Tai; Dustin J. Hines; Brian A. MacVicar. Brain Research Centre, 323 D205 Vancouver VESICLE DYNAMICS MEASURED IN DROSOPHILA NEURONS USING FLUORESCENCE CORRELATION SPECTROSCOPY Muscarinic stimulation generates prolonged depolarizations called Bryan A. Stewart, Cecile Fradin. Dept. of Biology, University of Toronto, plateau potentials (PPs) in hippocampal pyramidal neurons (Fraser and Dept. of Physics and Astronomy, McMaster Unversity MacVicar, 1996). PP is an attractive candidate for a major intrinsic conductance observed during ictal phase of seizures. Transient receptor Although the process by which membranous vesicles move within cells potential (TRP) channel subtype TRPC5 can generate non-selective cation is generally accepted, we are now only beginning to probe the dynamic conductances evoked by muscarinic receptor activation. Muscarinic nature of this essential cellular function. We particularly lack understanding activation also enhances TRPC5 protein translocation and insertion in the of the dynamics of neurotransmitter-containing synaptic vesicles within the plasma membrane of cultured hippocampal neurons (Bezzrides et al., 2004). nerve terminal. Two fundamental questions remain open: Are synaptic We hypothesized that plateau potentials and tail currents in CA1 vesicles mobile in the resting nerve terminal and if so, by what mechanism hippocampal pyramidal neurons are partially mediated by the muscarinic do they move? It is generally thought that the actin cytoskeleton plays a role induced membrane insertion and activation of TRPC5 channels. In order to in local vesicle trafficking but this assumption is relatively untested and the evaluate this hypothesis, we developed an assay for biotinylation in acute few studies to address the role of actin have yielded mixed results. Using hippocampal slices in order to quantify the change in membrane proteins FRAP analysis it was recently found that vesicles in the resting Drosophila during treatment with a muscarinic agonist, carbachol (CCH). After 15 min nerve terminal are highly mobile at rest and that disruption of the actin in CCH the surface expression of TRPC5 channels was increased by >15 cytoskeleton, either by pharmacology or genetics, reduced vesicle dynamics. fold. A control membrane protein, the transferrin receptor (TfR) showed no To further address the question, we have performed fluorescence correlation change. Atropine, the muscarinic antagonist, decreased the enhancement of spectroscopy experiments (FCS) in the same system, which allowed probing TRPC5 surface expression by CCH. We also used whole cell patch clamping the local mobility of synaptic vesicles at different loci within neuronal of CA1 pyramidal neurons in hippocampal slices to determine the boutons. The FCS study confirmed that synaptic vesicles were highly mobile, contribution of TRPC5 currents to the tail current that generates the PP. We and showed that the motion detected is consistent with diffusion. We also found that the common TRPC5 antagonists 2-APB and SKF-96365 could confirmed that the motion of the synaptic vesicles is on average slowed down significantly depress the tail current as well as PP. Interestingly, the PI3K following perturbation of filamentous actin. We therefore conclude that inhibitor wortmannin, which was shown to block translocation of TRP Drosophila synaptic vesicles are moving in an actin-dependent manner and channels in recombinant systems, could also decrease PP as well as surface that the combination of genetics and FCS provides a powerful method for expression of TRPC5 channels. Our results suggested that the rapid probing intracellular organelle dynamics. translocation of TRP channels contributes to the generation of PPs. This study provides a further understanding into the mechanisms of Ca2+ signaling after muscarinic stimulation and the pathology of epilepsy. 324 D206 EXAMINATION OF THE ROLE OF SCRIBBLE IN CULTERED HIPPOCAMPAL NEURONS 326 D208 Sun, Y. *, Yoshida E., Aiga M., Bamji SX. Department of Cellular and A PERSISTENT, VOLTAGE-DEPENDENT CALCIUM CURRENT IN Physiological Sciences. Brain Centre. University of British Columbia, NEUROENDOCRINE CELLS Vancouver A.K.T. Tam and N.S. Magoski. Department of Physiology, Queen's University, Kingston We have recently demonstrated that cadherin/-catenin adhesion complexes play a large role in localizing synaptic vesicles to developing Prior activity can modify the intrinsic excitability of neurons. A striking synapses. A detailed analysis of -catenin functional domains example of such activity-dependent change is the afterdischarge of the bag revealed that the PDZ-binding motif is essential for vesicle localization. We cell neurons from Aplysia californica. Following brief synaptic input, these have taken a candidate approach to identify the PDZ-domain containing neurons exhibit a 30 min burst of action potentials, resulting in the secretion protein(s) downstream of beta-catenin that mediates its effects. Scribble, a of egg-laying hormone and the initiation of ovulation. In cultured bag cell

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neurons, stimulation with a 5 Hz, 10 second train of action potentials results 328 D210 in a prolonged depolarization that extends well beyond the initial stimulus MGLUR5-INDUCED LONG-LASTING POTENTIATION OF L- and is analogous to the afterdischarge. A voltage-independent, non-selective TYPE CALCIUM CHANNELS IN DENDRITES OF HIPPOCAMPAL cation current, activated by the initial calcium influx, drives the prolonged CA1 ORIENS/ALVEUS INTERNEURONS depolarization; however, this current inactivates long before the end of the Lisa Topolnik*, Joe Guillaume Pelletier, Jean-Claude Lacaille. Dépt. de depolarization. Therefore, we examined the role of a persistent calcium Physiologie, Groupe de recherche sur le système nerveux central, Université current, activated by modest depolarization, in the maintenance of the de Montréal, Montréal, Québec prolonged depolarization. Calcium currents in cultured bag cell neurons were isolated under whole-cell voltage-clamp by replacing intracellular Voltage-sensitive calcium channels (VSCCs) provide a major source of potassium with cesium and extracellular sodium and potassium with TEA Ca2+ influx in neuronal dendrites and are involved in the regulation of and cesium, respectively. Currents were elicited from a holding potential of multiple cellular functions like dendritic electrogenesis, synaptic plasticity -60 mV, using step depolarizations from -50 mV to -20 mV for durations of and gene expression. However, the distribution, regulation and role of a minimum of 10 sec to a maximum of 3 min. The onset of voltage- VSCCs in dendrites of inhibitory interneurons are largely unknown. Here we activation for the persistent calcium current was between -50 mV and -40 use two-photon Ca2+ imaging in combination with whole-cell current-clamp mV. Once activated, the current was still present after 3 min, and displayed recordings to study the contribution of different types of VSCCs to dendritic only a slow decay by this point. Calcium currents were completely blocked Ca2+ transients evoked by backpropagating action potentials (bAPs-CaTs) by 10 mM nickel; moreover, 20 or 50 micromolar SKF96365, an agent and their regulation by the group I metabotropic glutamate receptors known to inhibit certain calcium permeable channels, partially blocked the (mGluRs) in CA1 oriens/alveus inhibitory interneurons. We find that L-, persistent calcium current. The effect of SKF96365 appeared to be voltage- P/Q- and R/T-types of VSCCs as well as ryanodine-sensitive Ca2+ stores dependent, with greater block at more depolarized potentials. Because the contribute to dendritic bAPs-CaTs. Local activation of mGluR5 produces persistent calcium current was maintained, even after 3 min of activation, it slow Ca2+ response followed by long-lasting potentiation of bAPs-CaTs. may be recruited during the initial excitation caused by the cation current. This bAPs-CaT potentiation does not involve P/Q- or R/T-types of VSCCs, The interaction between these two, distinct currents likely maintains the requires ryanodine-sensitive Ca2+ stores, is associated with an increased prolonged depolarization, and represents a potential general mechanism for contribution of L-type VSCCs and can be elicited by synaptic stimulation. activity-dependent changes to excitability. Our results suggest that the efficacy of dendritic L-type VSCCs can be potentiated for a long term via mGluR5- and Ca2+ release-dependent mechanisms in inhibitory interneurons. Specific mGluR5-dependent 327 D209 potentiation of L-type VSCC function represents a powerful synaptic REGULATION OF SYNAPTIC VESICLE DYNAMICS BY mechanism regulating dendritic excitability and likely synaptic plasticity in CADHERIN-ADHESION COMPLEXES interneurons. Lucía Tapia (1) and Shernaz X. Bamji (1,2). (1) Department of Cellular and Physiological Sciences. (2) Brain Research Centre. University of British Columbia 329 D211 CASPASE INHIBITOR (BAF) SELECTIVELY ENHANCES The rapid formation and elimination of synaptic sites occurs throughout NEURONAL SURVIVAL IN THE ADULT DENTATE GYRUS life and represents one aspect of synaptic plasticity in which synaptic Peggy W. Law*, J. Martin Wojtowicz. Department of Physiology, University communication is modified in the long-term. Little is known about what of Toronto determines where synapses will form along an axon or how are they modulated by neuronal activity. Synaptic adhesion proteins are of particular Two competing processes exist in the adult hippocampus: neurogenesis interest in this context because pre- to postsynaptic membrane adhesion is and apoptosis. Thousands of progenitors are generated each day in the one of the initial events during synapse formation and remains a fundamental dentate gyrus (DG) but >50% die before reaching maturity. Apoptosis component of the maintenance of synapses in maturity. We have previously removes neuroblasts that are not recruited into some functional role by the shown a role for the cadherin adhesion complex in the localization of critical second week. This process is important for both regulating the synaptic vesicles to developing presynaptic compartments. The maintenance dimension and neuronal circuitry in the adult DG. The objective of this study of strong cell-cell adhesion is detrimental to the formation of new synapses is to clarify the role of apoptosis in DG neurogenesis. To address this, we in the presence of the plasticity factor brain-derived neurotrophic factor used a broad-spectrum caspase inhibitor (BOC-Asp-CH2F or BAF) to (BDNF). Using time-lapse confocal analysis we showed that BDNF prevent apoptosis. Caspases are a family of proteases essentially involved mobilizes synaptic vesicles at existing synapses, resulting in small clusters of in apoptosis and are expressed in the adult DG. Three-month old male synaptic vesicles “splitting” away from synaptic sites. We demonstrate that Sprague-Dawley rats received two injections of bromodeoxyuridine (BrdU) BDNF’s ability to mobilize synaptic vesicle clusters depends on the within one day to label proliferating cells. Nine days later, either BAF (n=7) dissociation of cadherin/-catenin adhesion complexes. Artificially or saline (n=5) was perfused directly into the DG over three consecutive maintaining cadherin/-catenin complexes in the presence of days. Rats were sacrificed one day following the end of treatment. BDNF, abolishes the BDNF-mediated enhancement of synaptic vesicle Immunohistochemical markers were used to identify progenitors (BrdU) and mobility, and also abolishes the longer-term BDNF-mediated increase in neuroblasts (doublecortin or DCX) respectively. Our results demonstrate synapse number. We are now further exploring the hypothesis that enhanced that immediate survival of progenitors and neuroblasts was enhanced in two synaptic vesicle mobility contributes to the formation of new synapses, and of three DG regions after caspase inhibition. In the medial region, number that disruption of strong cadherin-based adhesion catalyzes this event. of BrdU+ and DCX+ increased by 25.7% and 36.0% in BAF-treated animals. Together, we believe that the molecular adhesive machinery required for In the ventral region, number increased by 24.4% and 39.9%. BAF did not synapse assembly in development plays an essential role in modulating appear to influence differentiation of progenitors; over 75% of progenitors synaptic architecture in the context of plasticity-related structural develop into neuroblasts in both groups. Therefore, we conclude that: 1) a remodeling. considerable number of one-week old progenitors face elimination through a caspase-dependent mechanism and 2) reducing caspase activity can enhance their immediate survival. As the hippocampus is involved in various forms of learning and memory, more DG neurons could improve either process. Furthermore, this study is the first to reveal a difference in sensitivity to

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caspase inhibition across DG regions. This can be partly attributed to the “hidden” (and thus “inactive”) ion channels/transporters in modulation of variable rate of apoptosis occurring in each region. (This study is supported axonal excitability. We tested this hypothesis by analyzing the by CIHR). electrophysiological properties of white matter axons in mature rat spinal cord and have found that the decay phase of their action potentials can be modulated by axonal activity. We show that the fast K+ channel blocker 4- 330 D212 aminopyridine, which normally does not have effects on action potentials of ULTRASTRUCTURAL LOCALIZATION OF EPHRIN-B3 IN ADULT myelinated axons due to its inability to reach the K+ channels concealed RAT HIPPOCAMPUS under the myelin sheath, becomes effective after periods of increased axonal M.È. Tremblay, M. Riad and G. Doucet. Département de pathologie et activity. These results can be interpreted in terms of transient disconnection biologie cellulaire and Groupe de recherche sur le système nerveux central, of paranodal myelin loops from the axonal membrane, thus opening ways for Université de Montréal 4-AP to diffuse into the adaxonal space under the myelin sheath to block K+ channels. The proposed hypothesis emphasizes a dynamically changing Recent observations suggest that interactions between the picture of myelin-axonal interactions at and around the node of Ranvier and transmembrane ligand, ephrin-B3, and the EphA4 or EphB2 receptors may have a wide range of applications in normal physiology and influence synaptogenesis, as well as the induction of long-term potentiation pathophysiology of myelinated axons. (LTP) in regions CA1 and CA3 of rodent hippocampus. A detailed analysis of the discrete cellular distribution of ephrin-B3 within the hippocampal circuitry is currently needed in order to better understand the exact role of 332 D214 this molecule in such processes; notably its pre- or postsynaptic interactions VOLTAGE-DEPENDENCE OF EXCITATION-TRANSCRIPTION with any of the two receptors. In situ hybridization had previously shown COUPLING: SIGNALING FROM CALCIUM CHANNELS TO ephrin-B3 expression in CA1 and CA3 pyramidal cells, and in dentate gyrus CREB (DG) granule cells, but the subcellular localization of the protein has not been Damian G. Wheeler*, Curtis F. Barrett and Richard W. Tsien,. Department of examined at the ultrastructural level. We used light and electron microscopic Molecular and Cellular Physiology, Stanford University immunocytochemistry with a polyclonal anti-ephrin-B3 antibody, whose specificity was tested in brain sections from ephrin-B3 knockout mice Excitation-transcription (E-T) coupling provides a vital link between (provided by Dr. Henkemeyer). Ephrin-B3 immunoperoxidase labeling was electrical activity and gene expression in excitable cells. This process is of observed in the cell body and neuropil layers of CA1, CA3, and DG, where great importance for the development and remodeling of cellular structure it was most frequently observed in axon terminals, including mossy fiber and function but is not thoroughly understood with respect to fundamental terminals. Labeled neuronal perikarya and astrocytic processes were also aspects of signal transduction. Classic studies of both excitation–contraction frequent. Dendritic spines, dendritic shafts, unmyelinated and myelinated (E-C) and excitation–secretion (E-S) coupling have demonstrated the axons were only occasionally labeled. Labeled axon terminals made synaptic biological output is steeply dependent upon voltage-dependent calcium contact with generally unlabeled dendritic spines, dendritic shafts and channel (VDCC) activity; however, little is known about the detailed kinetics neuronal perikarya, in decreasing order of frequency. The synapses between of E-T coupling. The transcription factor CREB plays important roles in ephrin-B3 axon terminals and dendritic spines were generally asymmetrical long-term neuronal plasticity and is thus one of the most widely studied and displayed features of excitatory synapses; whereas those with dendrites mediators of E-T coupling. In this study we examined the relationship or perikarya were symmetrical. The ephrin-B3 labeling of Schaffer collateral between depolarization by extracellular K+ elevation and signaling to and mossy fiber axon terminals is consistent with its proposed role in LTP at nuclear CREB, using cultured neonatal rat superior cervical ganglion (SCG) both types of synapses. We recently reported that EphA4 is localized in the neurons as a model system. We found that depolarizing SCG neurons pre- as well as post-synaptic partners of these synapses (Tremblay et al., J activated L-type channels resulting in a rapid phosphorylation of CREB that Comp Neurol 501:691, 2007), whereas EphB2 was most frequently detected was graded by both stimulation duration and voltage. To gauge the strength in dendritic shafts and less often in spines (Bouvier at al., submitted). Thus, of the signal, we monitored the relationship between stimulation duration and the above ephrin-B3 localization appears more consistent with interactions the extent of CREB phosphorylation and determined that, like E-C and E-S with EphA4 than EphB2; which will need confirmation by ongoing dual coupling, CREB signaling strength is steeply voltage-dependent with an e- labeling experiments. Supported by NSERC. M.-È.T. is supported by fold increase per 5.6 mV. Importantly, this steep relationship was determined studentships from FRSQ and UdeM. largely by voltage-dependent changes in L-type channel open probability (Po). By grading Ca2+ flux through the channels while keeping depolarization constant, we discovered that CREB phosphorylation shows a 331 D213 surprisingly shallow dependence on unitary Ca2+ channel flux (i). Thus, DYNAMIC GLIAL-AXONAL INTERACTIONS AT THE NODE OF Ca2+ entry through L-type channels is essential for signaling to CREB, but RANVIER: NORMAL FUNCTIONS AND IMPLICATIONS TO the strength of the signal is only weakly affected by gradations in the PATHOPHYSIOLOGY OF SPINAL CORD INJURY magnitude of the Ca2+ flux or resulting rise in bulk [Ca2+]. We ruled out the *Velumian A.A.(1,3,4) and Fehlings M.G.(1-4). (1)Toronto Western Hospital idea that conformational changes in the L-type channel directly engage signal and (2)Krembil Neuroscience Center, University Health Network; transduction machinery to account for the apparent voltage-dependence (3)Departments of Surgery and (4)Physiology, University of Toronto above and beyond that of Ca2+ flux. Rather, we propose that Ca2+ entering the cell through L-type channels saturates a Ca2+ sensor in a local Ca2+ Glial-axonal interactions at the node of Ranvier are key factors defining nanodomain, such that decreases in i have little effect on sensor activation. the excitability of myelinated axons in health and disease. In myelinated When neurons are depolarized, increases in Po recruit more and more axons, K+ channels are located predominantly under the myelin sheath, and channel signaling modules, which mediate signaling to CREB in a their role in normal physiology remains unknown. These channels are cooperative manner. typically viewed in terms of their negative effects on axonal function following injury or with disease, when they become exposed due to retraction or breakdown of the myelin sheath. We hypothesized that paranodal myelin loops, which segregate the Na+ channel-rich nodal area from the rest part of the axon, may transiently disconnect from the axonal membrane in response to increased axonal activity, providing conditions for recruitment a normally

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333 D215 cell division. We have localized chTOG (CKAP5 in chicken) to the axonal NERVE GROWTH FACTOR INCREASES THE EXPRESSION OF cytoplasm in chick sensory ganglia using immunocytochemistry. chTOG ΜU OPIOID RECEPTOR PROTEIN IN PC12 CELLS strongly stains the axon initial segment, nodes of Ranvier, and the growth Warren Winick*, Francesco Leri^, Bettina Kalisch*. Departments of cone, which are all areas of high MT dynamics in neurons. The MT- Biomedical Sciences* and Psychology^, University of Guelph, Guelph disrupting drug nocodazole was used to investigate whether chTOG distribution is altered in the absence of MTs in the growth cone. Short The goal of this work is to elucidate the cellular mechanisms regulating interference RNAs (siRNAs) were designed against chTOG and were mu-opioid receptor (MOR) expression. We therefore investigated MOR successfully co-transfected with GFP into primary neurons. These indicate protein levels in PC12 cells treated with nerve growth factor (NGF). Using that chTOG plays a functional role in MAP-dependent MT regulation in the Western immunoblotting with rabbit anti-MOR (abcam) and cAMP analysis, axonal cytoplasm. we found a significant increase in MOR expression after 72 hours of NGF (50 ng/ml) treatment. We then explored whether this NGF-mediated increase in MOR expression is regulated by nitric oxide (NO). It was found that pre- 336 D218 treatment of PC12 cells with NO synthase (NOS) inhibitors Nω-nitro- THE CELLULAR MECHANISMS UNDERLYING GABAergic L-arginine methyl ester (L-NAME) (20 mM) and s-methylisothiourea (S- SYNAPTIC PLASTICITY MIU) (2 mM) had no effect on NGF induced MOR expression, although Trevor Balena* and Melanie Woodin. Department of Cell & Systems Biology, significant increases in MOR levels were detected as a result of pre-treatment University of Toronto with S-MIU alone. From these data, it appears that the NGF-mediated increase in MOR protein expression is not due to NGF induced increases in Coincident pre- and postsynaptic activity decreases the strength of NOS or NO. Supported by NSERC and CIHR synaptic inhibition in the hippocampus. The magnitude and polarity of this spike-timing dependent synaptic plasticity (STDP) depends of the spike- timing interval used during plasticity induction. When the spike-timing 334 D216 interval is correlated (within ±20 ms, pre-post or post-pre) a persistent NA+/CL- DIPOLE COUPLES AGONIST BINDING TO KAINATE increase in the amplitude of the inhibitory postsynaptic current (IPSC) is RECEPTOR ACTIVATION recorded. This increase in IPSC amplitude is due to a positive shift in the Adrian Y.C. Wong, David M. MacLean and Derek Bowie. Department of reversal potential for GABA (EGABA), thus STDP of GABAergic synapses Pharmacology and Therapeutics, McGill University, Montreal produces a decrease in the overall strength of inhibition. In the present study we examined the role of postsynaptic Ca2+ in the regulation of EGABA Kainate-selective ionotropic glutamate receptors (iGluRs) require during STDP induction. We made simultaneous electrophysiological and external Na+ and Cl- as well as the neurotransmitter, L-glutamate, for fluorescence imaging recordings using Fluo-4AM from hippocampal activation. Although, external anions and cations apparently co-activate neurons cultured at low-density Following the electrophysiological kainate receptors (KARs) in an identical manner, it has yet to be established identification of GABAergic synapses, we determined the postsynaptic Ca2+ how ions of opposite charge achieve this. A further complication is that dynamics at the soma and synapse during the induction of GABAergic STDP. KARs are subject to other forms of cation-modulation via extracellular Both coincident (pre-post +10ms) and non-coincident (pre-post +100ms) acidification (i.e. protons) and divalent ions. Consequently, other cation protocols (5Hz, 30sec) were examined. We found that the magnitude of the species may compete with Na+ to regulate the time KARs remain in the open postsynaptic Ca2+ increase during coincident induction protocols was state. Here we have designed experiments to unravel how external ions dependent on both the synaptic amplitude and EGABA of the synapse. regulate GluR6 KARs. We show that GluR6 kinetics are unaffected by Synapses with larger currents and a more hyperpolarized EGABA produced alterations in physiological pH but that divalent and alkali metal ions smaller Ca2+ increases, when compared with synapses that had smaller compete to determine the time course of KAR channel activity. Additionally, synaptic amplitudes and more depolarized EGABA values. Non-coincident Na+ and Cl- ions co-activate GluR6 receptors by establishing a dipole protocols produce that same magnitude of Ca2+ as compared with accounting for their common effect on KARs. Using charged amino acids as postsynaptic spiking alone. Thus GABAergic STDP requires a Ca2+- tethered ions, we further demonstrate that the docking order is fixed with dependent depolarization of EGABA. We are currently examining how Ca2+ cations binding first, followed by anions. Taken together, our findings regulates K+-Cl- cotransport (KCC2) at the molecular level; KCC2 regulates identify the dipole as a novel gating feature that couples neurotransmitter EGABA in the mature CNS. binding to KAR activation. Supported by operating grants from the CIHR to D.B. A.Y.C.W was funded by the David T.W. Lin fellowship and D.M.M by a predoctoral fellowship from the CIHR. D.B. is the recipient of a Canada 337 D219 Research Chair award. SIMULTANEOUS TIME-LAPSE CONFOCAL IMAGING AND ELECTROPHYSIOLOGY REVEALS THAT ATP P2Y RECEPTOR- COUPLED OUTWARD POTASSIUM CURRENT UNDERLIES 335 D217 MICROGLIAL CHEMOTAXIS chTOG, A NEW AXONAL MICROTUBULE-ASSOCIATED Long-Jun Wu, Kunjumon I. Vadakkan, Min Zhuo. Department of Physiology, PROTEIN WITH A DISTINCT PATTERN OF DISTRIBUTION Faculty of Medicine, and Centre for the Study of Pain, University of Toronto F. K. Wong* & E. F. Stanley. Genes, Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto Microglial cells are the resident macrophages that are involved in brain injuries and infections. Recent studies using transcranial two photon Microtubules are critical components of the cytoskeleton that serve as microscopy have shown that ATP and P2Y receptors mediated rapid structural scaffolds and tracks for axonal transport. However, the mechanism chemotactic responses of miroglia to local injury. However, the molecular whereby these fibers are regulated during axonal growth, regeneration, and mechanism for microglial chemotaxis towards ATP is still unknown. To retraction is complex and poorly understood. One of the ways that MTs are address this question, we employed a combination of simultaneous regulated is through interactions with microtubule-associated proteins perforated whole-cell recordings and time-lapse confocal imaging in GFP- (MAPs). A proteomic screen of rat brain synaptosomes identified chTOG, or labeled microglia in acute brain slices from adult mice. We found that ATP- colonic and hepatic tumor over-expressing gene, a MAP that is well induced rapid chemotaxis is correlated with P2Y receptor associated-outward characterized in mitotic cells and essential in MT spindle formation during potassium current in microglia. Activation of both P2Y receptor and its

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associated potassium channels are required for ATP-induced chemotaxis and intracellular reactive oxygen species as well as localized decreases in baseline motility of microglial cells. The chemotaxis required the activation extracellular calcium; events known to occur in the brain during ischemia. of phosphoinositide 3-kinase but not mitogen-activated protein kinase The present study aims to isolate the regions of TRPM7 responsible for pathway. Our results provide strong evidence that P2Y receptor-associated mediating its response to oxidative stress. In particular, we chose to focus on outward potassium channels and the phosphoinositide 3-kinase pathway are the C-terminal PDZ-binding motif. PDZ domains enable intermolecular important for ATP-induced microglial motility in acute brain slices. This protein assembly through PDZ-PDZ interactions and by binding to C- work is supported by NeuroCanada Brain Repair program. Long-Jun Wu is terminal consensus motifs. We began by generating a truncated construct of supported by postdoctoral fellowships from the Canadian Institutes of Health the TRPM7 channel that contained a deletion of the 9 C-terminal amino acids Research and Fragile X Research Foundation of Canada. (corresponding to positions P0 to P-8 with respect to the PDZ-binding motif), thereby disrupting intracellular interactions mediated by the PDZ-binding motif. Briefly, constructs containing the full-length and truncated TRPM7 338 D220 sequences were studied by heterologous expression in HEK-293T cells. Cells TIMING OF ACTION POTENTIAL EVOKED CA2+ CURRENT IN were exposed to treatment with sodium cyanide (NaCN) to mimic the anoxic TRIGGERING TRANSMITTER RELEASE AT THE CALYX OF conditions of cerebral ischemia. We focused on two parameters as indicators HELD SYNAPSE of TRPM7 activity: calcium uptake and cell death. Calcium uptake was Yi-Mei Yang and Lu-Yang Wang. Neuroscience & Mental Health, The monitored using the fluorescent intracellular calcium indicator fluo-3, and Hospital for Sick Children and Department of Physiology, University of levels of cell death assessed by propidium iodide (PI) uptake. We found that Toronto expression of the full-length and truncated constructs significantly increased calcium uptake induced by NaCN. Cell death, however, was increased only Action potentials (APs) play a crucial role in evoking presynaptic Ca2+ in cells expressing the full-length TRPM7 channel, suggesting a role for the currents (ICa) and controlling neurotransmitter release, but little is known PDZ-binding motif in mediating cytotoxic signaling events downstream of about how AP waveform determines the timing of Ca2+ influx as well as its channel activation. relationship to quantal output in central synapses. By paired voltage-clamp recordings of ICa and excitatory postsynaptic currents (IEPSC), we examined these issues with pseudo- and real-APs at the calyx of Held 340 D222 synapse. We found that at 22°C the timing of Ca2+ entry strongly depended PHOSPHORYLATION OF CREB STIMULATED BY IGF-1 IN PC12 on AP repolarization rate but not depolarization rate, being immediately after IS MEDIATED BY MITOGEN AND STRESS ACTIVATED the completion of repolarization phase for short APs and advanced towards PROTEIN KINASE (MSK1) the early part of repolarization phase as APs were broadened. At 35°C, ICa Zheng WH*&+ Li RF&, Huang M&, Liu PQ&, Yao LM &, Han C& and evoked by real APs remained as tail currents, but Ca2+ influx evoked by Quirion R+. & Neuropharmacology, School of Pharmaceutical Sciences, pseudo-APs with slower time course than real APs could occur as early as in Sun Yat-Sen University, Guangzhou , China;+ Douglas Hospital Research the depolarization phase. Comparison of voltage-dependence of ICa at two Center, McGill University, Montreal, Canada temperatures revealed that raising temperature from 22°C to 35°C led to a temperature-dependent shift in the activation threshold of ICa and an Insulin-like growth factor-1 (IGF-1) is a polypeptide growth factor with accelerated kinetics in activation and deactivation. As a result of fast gating a variety of functions in both neuronal and non-neuronal cells. IGF-1 kinetics of ICa, timing of Ca2+ entry was shifted to from the repolarization promotes its biological functions by activating multiple signaling pathways phase to the depolarization phase of pseudo-APs, provided that the latter including PI3/Akt and MAPK pathways. We have previously shown that phase is sufficiently slow (>0.5 ms). These results presented the proof of IGF-1 stimulates the phosphorylation of the Ca 2+/cAMP response element- principle that timing of Ca2+ inflow is highly dependent on the AP binding protein (CREB) at Ser-133 residue in PC12 cells (Zheng et al., waveform, kinetics of ICa and temperature. Interplay of these variables 2006). However, the kinase involved in IGF-1-induced phosphorylation of dictates the timing of Ca2+ influx and ultimately quantal output. We also this transcriptional factor is not clear. We report here that MSK1, a have evidence to suggest that ICa in the form of tail currents helps preserve downstream target of MAPK and p38 MAPK kinase, is involved in IGF-1 temporal precision in presynaptic input and postsynaptic response, and is an stimulated phosphorylation of CREB. IGF-1 induced the phosphorylation of important adaptation for achieving high-fidelity neurotransmission at the both CREB, MSK1, FOXO3a and Akt in PC12 cells. The phosphorylation of calyx of Held synapse. Support Contributed By: BWF & CIHR CREB and MSK1 was dependent on the activation of MAPK and p38 MAPK, but that of FOXO3a was relied on the PI3 kinase/Akt. Inhibition of MAPK by PD98059 or the p38 MAPK blocker PD169316 significantly 339 D221 inhibited IGF-1-mediated phosphorylation of MSK1 and CREB. But had no MUTAGENIC ANALYSIS OF TRPM7 CHANNEL FUNCTION IN effect on FOXO3a.Moreover, H89 and Ro318220, inhibitors of MSK1, dose- ANOXIA dependently blocked IGF-1-induced CREB phosphorylation. These data Jennie Yum*, Michelle M. Aarts, Michael Tymianski. Fundamental suggest that the activation of MSK1 via MAPK and p38 MAPK is involved, Neurobiology, Toronto Western Research Institute, Toronto at least in part, in IGF-1 stimulated phosphorylation of CREB in PC12 cells. Supported by CIHR and NFSC 30670652. Neurons that die following an ischemic attack exhibit an increase in the formation of reactive oxygen species, and experience excessive influx of calcium leading to neuronal death. While it has previously been shown that 341 D223 specific effectors downstream of calcium-activation may mediate apoptosis EPHA4 SIGNALING REGULATES PHOSPHOLIPASE C GAMMA 1 and necrosis, the contribution of a novel class of ion channels, belonging to ACTIVATION, COFILIN MEMBRANE ASSOCIATION, AND the Transient Receptor Potential (TRP) channel superfamily, has also been DENDRITIC SPINE MORPHOLOGY implicated in cellular degeneration of these cells. In previous work we have Lei Zhou*, Sarah J. Martinez, Michael Haber, Emma V. Jones, Andreas found that specific knockdown of the TRPM7 channel prevents neurons from Zisch, and Keith K. Murai. Centre for Research in Neuroscience, Department dying following anoxic insult (Aarts et al., 2003). TRPM7 channels provide of Neurology and Neurosurgery, The Research Institute of the McGill a pathway for mono- and divalent cations into the cell and are unique in that University Health Centre, Montreal General Hospital, Montreal, and they contain a functional, C-terminal alpha-kinase domain. More relevantly, Institute of Obstetrics, University Hospital Zurich, Zurich, Switzerland the channel is thought to be activated in response to the generation of

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Dendritic spines are highly specialized structures protruding from neuronal volume is rapidly and transiently regulated during high K+ induced dendritic shafts that form the postsynaptic sites for the majority of spreading depression by activation of NHE and KCC2 transporters. glutamatergic excitatory synapses in the brain. In general, a spine is composed of an enlarged head region and a constricted neck and serves as biochemical compartment that accommodates the postsynaptic density 343 D225 (PSD), a dense region of ion channels and receptors that are complexed with REGENERATION OF INJURED PERIPHERAL NERVES: scaffolding and other signaling proteins. Spines are actin-rich structures, and ROLE OF THE MICROENVIRONMENT undergo rapid structural remodeling. These changes are believed to be McDonald D, Cheng C, Toth C, Chen YY, Webber C, Zochodne DW. associated with modifications of synaptic physiology that underlies the Department of Clinical Neurosciences and the Hotchkiss Brain Institute, cognitive processes like learning and memory. However, the mechanisms University of Calgary that regulate actin organization and structural plasticity of spines are only beginning to be identified. We recently reported that activation of the EphA4 Despite assumptions otherwise, peripheral nerve injuries are associated receptor tyrosine kinase upon ephrin ligand binding induced spine retraction with substantial, severe and irreversible disabilities that highlight the barriers in hippocampal neurons. However, the signaling pathways downstream of to their regeneration. Over the last 3 years, our laboratory has explored early EphA4 that regulates spine morphology remain unknown. Here, we barriers that develop following transection injuries of peripheral nerves. demonstrate that ephrin stimulation of EphA4 leads to the recruitment and Transection, a common clinical injury, involves the complete separation of activation of phospholipase Cgamma1 (PLCg1), which is known to be the proximal and distal stump of a peripheral nerve trunk. It is estimated that involved in membrane phosphoinositide regulation. We show that the only 10% of transected axons successfully regenerate to distal targets. interaction between PLCg1 and EphA4 requires an SH2-domain of PLCg1 Our approach involves an accessible conduit that connects proximal and and juxtamembrane tyrosines of EphA4. We also show that PLC activity is distal nerve stumps and can be manipulated from a subcutaneous access port required for the maintenance of spine morphology and ephrin-induced spine 1. We highlight several findings identified by this window on early retraction in hippocampal slices. Interestingly, PLCg1 modulates the plasma regenerative events. Firstly, we have observed that early regeneration is membrane association of the actin depolymerizing/severing factor, cofilin, highly limited and staggered indicating profound hostility to regrowth 2. which has previously been implicated in actin filament regulation and the Barriers to regrowth may operate in part through RhoA/Rho kinase (ROK) remodelings of dendritic spines. EphA4 and PLCg1 signaling may thus axon signalling pathways independent of myelin inhibitors: pharmacological modulate the actin cytoskeleton and spine morphology through cofilin inhibition of ROK with HA1077 enhanced new axon regrowth not exposed regulation at sites of ephrin-EphA4 contact. to inhibitors in the distal nerve stump 3. A number of additional features of the microenvironment impair regeneration. An intense local inflammatory response substantially impairs early regeneration, in part because of local 342 D224 release of nitric oxide. The presence of diabetes mellitus also adds substantial RAPID CHANGES IN NEURONAL VOLUME EVOKED BY barriers to nerve outgrowth and consolidation. Secondly, early axon SPREADING DEPRESSION outgrowth rarely occurs in isolation, but instead depends on an intimate Ning Zhou* and Brian A MacVicar association with Schwann cell (SC) processes. This association is almost invariable, with fidelity through three dimensions of space irrespective of the Spreading depression (SD) is a propagating wave of neuronal and irregularity of the trajectory. Regrowth depends on the ability of SCs to astrocytic depolarization important in the pathogenesis of migraines, proliferate and guide following axons; inhibition of SC mitosis severely ischemia and brain trauma. SD in the grey matter is associated with a shift in disrupts regeneration 4. One of the critical signals between axons and SCs extracellular potentials and transient depression of synaptic transmission. cells may be axonally synthesized CGRP peptide. Its receptors CRLR and This can be directly monitored as an increase of light transmittance of the RAMP-1 are expressed by SCs and local interruption of either CGRP tissue, called the intrinsic optical signals (IOSs). Interestingly, extracellular synthesis or RAMP-1 synthesis using siRNA, interrupts regeneration 5. space shrinks during SD, indicating that brain swelling may involve a Overall, understanding how axon-SC interactions overcome the local barriers neuronal component. SD was induced in cortical slices by bath perfusion of of the regenerative milieu to regrow is of substantial importance in peripheral high potassium (40 mM of [K+]o) for 1.5 to 2 min. Using identified yellow neurobiology. [Supported by CIHR, CDA, AHFMR] 1. McDonald, D. S. & fluorescent protein positive neurons from the Thy1 transgenic mouse model, Zochodne, D. W. J. Neurosci. Methods 122, 171-178 (2003). 2.McDonald, we measured neuronal volume and IOS with two-photon laser scanning D., Cheng, C., Chen, Y. microscopy. Additionally, simultaneous measurements of whole-cell currents or field potentials were used to synchronize electrophysiological changes to IOSs. The high K+ evoked peak amplitudes of IOS, neuronal currents and 344 D226 field potentials occurred simultaneously. Neuronal volume increased EFFECT OF T-CHANNEL DISTRIBUTION ON FIRING PATTERN immediately following SD onset and peaked within about 1 minute. OF THE THALAMOCORTICAL CELL Interestingly, neuronal volume recovered to the control level by 4 to 5 Reza Zomorrodi, Helmut Kroger, Igor Timofeev. Physics Department, Laval minutes from the onset of SD. Intracellular pH, measured with DCECF University, Anatomy and Physiology Department, Laval University fluorescence indicated a transient acidification concurrent with the onset of SD. Since it has been suggested that neurons are resistant to osmolarity- The low-threshold calcium current (IT) underlies burst generation in the induced volume changes, we investigated the role of ion channels and thalamocortical (TC) relay cells and plays a central role in the genesis of transporters. Blockers of ion channels failed to affect high K+ induced synchronized oscillations by thalamic circuits. In thalamic relay cells neuronal volume increase. However, an inhibitor of the acid activated Na/H ascending and descending inputs arrive to distinct parts the dendritic tree. exchanger (NHE), amiloride partially blocked the volume increase, and Active properties of the dendritic tree influence synaptic integration. prolonged the recovery from SD induced acidification. This suggested a role Previous studies have developed some algorithms to determine active for additional transporters in volume regulation of neurons during SD. K/Cl parameters of the cell, but these methods are limited by number of free cotransporter (KCC) in pyramidal neurons normally exports K+ and Cl-. parameters. Here we developed a multicompartment model of However KCC2 can transport K+ inversely into cells under conditions of thalamocortical cell to consider effects of dendritic currents on response of elevated [K+]o thereby causing cell volume increase. Blockade of KCC2 the cell.We attribute uniform T-channel distribution for all compartments in with the inhibitor DIOA, similar to amiloride partially inhibited the neuronal model in order to find a threshold for Low Threshold Calcium Spike (LTS) volume increase. When applied together, amiloride and DIOA dramatically leading to action potential generation. By multiplication permeability of each reduced the SD induced change in neuronal volume. We conclude that section to its area we found a threshold number of channel that was necessary

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to reproduce an LTS. Next we tuned active parameters of dendrites by We studied transmembrane postreceptor signalling by trimeric G proteins considering different Gaussian distribution of T-channel for our 1270 - alpha subunits of main types using C6 glioma cells, natural killer (NK) compartments model. We normalized our Gaussian distribution to this cell line (RNK 16) or isolated human NK cells affected by antidepressants threshold value, then for different means and variances we examined LTS (SSRI) fluoxetine or sertraline. Also effects of iinterleukin 2, IL-2 or response and IV- curve of T-current. Our simulations show, independent of adenosine (NECA) agonist was assayed. Fluoxetine effects were found to the Ca2+ channel distribution, for a total channel number below the threshold decrese significantly G alpha q/11 levels in all tested cells. Acute effect of value, cell gives a passive response and above the threshold, model fluoxetine is linked to translocation of membrane G alpha q/11 into reproduces the LTS. However, in a small range below the threshold the cytoplasm besides lower effector response by PLC and thus decreased 1,3,5 difference between uniform and non uniform distributions becomes visible. IP3, 2nd messenger formation. We estimated similarities in G alpha profiles In the range 1-2 % below the threshold value the uniform distribution of T- in comparison with IL2 or NECA. Furthermore NECA effects interfered channel produced passive response while a non-uniform distribution with fluoxetine effects on G alpha levels but also on apoptosis events. On the reproduced LTS response. Compare to experimental data, firing patterns and other hand, sertraline effects influenced mainly G alpha (s) levels a no IV curve of T-current, shows a non-uniform distribution with higher density apoptosis was observed. When we summarized, acute action of fluoxetine in sections near to soma has more correspondence to experimental data. on G protein profiles In C6 glioma cells and NK cells were comparable with Supported by NSERC and CIHR immunostimulator IL-2. Thus these effects can operate via similar transduction points in both brain cells and immunocytes. Supported by grants MSM0021620849, GACR 524/05/0267 and MSM 6215712403. 345 D227 STRYCHNINE-MEDIATED EXCITATION OF MAGNOCELLULAR NEUROSECRETORY CELLS IS INVERSELY RELATED TO 347 D229 EXTRACELLULAR FLUID OSMOLALITY IN SUPERFUSED SSRI-TYPE ANTIDEPRESSANT MEDICATION MAY EXPLANTS OF RAT HYPOTHALAMUS COMPROMISE SEROTONERGIC CELL FUNCTION IN Yuri Choe and Charles W. Bourque. Montreal General Hospital - Research SELECTED RAPHE NUCLEI Institute, McGill University Lindsey MacGillivray, Patricia Rosebush, Michael Mazurek. McMaster University Application of strychnine has been shown to excite magnocellular neurosecretory cells (MNCs) in the rat supraoptic nucleus (SON) in vivo, Background: Selective serotonin reuptake inhibitors (SSRIs) are where strychnine is believed to act as a competitive antagonist to taurine- commonly prescribed for treatment of depression, anxiety, panic, obsessive- mediated activation of glycine receptors (GlyRs). In this system, taurine has compulsive and impulse-control disorders. It is well established that SSRI been shown to be released by astrocytes in the ventral glial limitans, which medications inhibit serotonin reuptake via blockade of serotonin transporters. arborize within and around the nucleus. Hypoosmotic conditions have been Neither the onset of therapeutic properties nor the induction of persistent side shown to increase the release of taurine, thereby inhibiting the electrical effects, however, correlates with transporter blockade; this suggests a activity of MNCs in order to suppress vasopressin and oxytocin release into mechanism more complex than simple inhibition of serotonin reuptake. We the bloodstream. Conversely, hypertonic conditions suppress the basal studied the time course of changes in serotonergic neurons in four raphe release of taurine and lessen GlyR-mediated inhibition on MNCs, leading to nuclei after initiation of SSRI medication. Methods: Groups of Sprague- an increase in electrical activity and VP release. In this study we investigated Dawley rats received daily meals of rice pudding either alone (N=9) or mixed if this process could be studied in vitro, in superfused explants of rat with the SSRI citalopram 5 mg/kg/day (N=27). Rats were sacrificed at 24 hypothalamus. We first examined the specificity of bath-applying 1 hours, 7 days or 28 days after initial administration. Sections of caudal linear μM strychnine for blockade of GlyRs. In single-unit extracellular nucleus (CLN), median raphe nucleus (MR), dorsal raphe nucleus (DR) and recordings from MNCs, bath-application of 1 μM strychnine raphe magnus (RM) nucleus were processed for tryptophan hydroxylase reversibly blocked the inhibitory effect of taurine, but not that of GABA. (TPH) immunohistochemistry. The number of TPH-positive cells was Indeed, application of strychnine significantly reduced the per cent inhibition determined by blinded, manual counting. Results were analyzed by one-way induced by taurine from 58.9 ± 8.4 to 18.4 ± 5.8 per cent (n=4; P<0.01), but analysis of variance (ANOVA) followed by post-hoc Tukey tests. Results: not those evoked by GABA (44.6 ± 2.6 to 30.7 ± 5.0 per cent (n=3; P=0.07)). Citalopram induced a significant 41% (p=0.001) reduction in DR TPH- We next examined whether the excitatory effect of strychnine depended on positive cell counts at 24 hours, 7 days (38%, p= 0.003) and 28 days (52%, the external osmolality by recording from MNCs under hypoosmotic (275 ± p<0.001). Downregulation in the DR was paralleled by reductions in TPH- 5 mosmol/kg) and isoosmotic (300 ± 5 mosmol/kg) conditions. The degree positive cell counts in the MR and RM. In the MR, citalopram caused of excitation induced by bath-applying 1 μM strychnine showed an significant reductions at 24 hours (26%, p=0.004), 7 days (16%, p=0.034) inverse relationship with respect to extracellular osmolality: The excitatory and 28 days (23%, p=0.012). Similarly, in the RM, citalopram induced a effect of strychnine was significantly greater in hypoosmotic (1.0 ± 0.3 Hz; significant (45%, p=0.009) reduction of TPH-positive cell counts at 24 hours, n=18) than isoosmotic medium (0.04 ± 0.3 Hz ;n=14; P<0.05). These results 7 days (34%, p=0.009) and 28 days (43%, p=0.006). No significant indicate that GlyRs mediate an inhibitory effect on firing rate in MNCs and differences between control and treatment groups were observed in the CLN that the strength of this inhibition varies as an inverse function of osmolality at any of the time points that we studied. Conclusions: These results indicate in superfused explants of rat hypothalamus. Whether this inhibitory effect is that citalopram can induce a regionally specific downregulation of brainstem mediated by taurine release from glial cells remains to be demonstrated. serotonergic neurons within 24 hours. This reduction in TPH- immunoreactive cell counts may play a role in mediating the therapeutic and toxic clinical effects of antidepressant use. 346 D228 NEUROIMMUNOMODULATORY ASPECTS OF CELL SIGNAL TRANSDUCTION (1)Kovaru H., (2,3)Kovaru F., (4)Fiserova A., (1)Havrdova E., (5) Lisa V.. (1) 1st Faculty of Medicine, Charles University, Prague, (2) University of Veterinary and Pharmaceutical Sciences, Brno (3) Institute of Animal Physiology and Genetics, Acad.Sci., Brno (4) Institute of Microbiology, Acad.Sci., Prague, (5) Institute of Physiology, Acad.Sci., Prague, Czech Rep.

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348 D230 350 D232 5-HT REGULATES THE APLYSIA TRK-LIKE RECEPTOR IDENTIFICATION OF TENEURIN C-TERMINUS ASSOCIATED (APTRKL) THROUGH TRAFFICKING OF THE RECEPTOR PEPTIDE (TCAP)-1 RESPONSIVE REGIONS OF THE BRAIN AS Ikue Nagakura(1), Jake Ormond(2) , Wayne Sossin(1). (1) McGill University, DETERMINED BY IMMUNOREACTIVE C-FOS INDUCTION (2) University of Toronto Laura Tan* (1,2), Franco J. Vaccarino (1,2,3), David A. Lovejoy (1), Susan Rotzinger (1,2,3). (1) Department of Cell and Systems Biology; (2) There is an important role for tyrosine kinases, especially Trk family of Department of Psychology; (3) Department of Psychiatry; University of receptor tyrosine kinases (RTKs), in learning and memory. In Aplysia, Toronto, Toronto, Canada previous study has shown that a Trk-like receptor, named ApTrkl, is required for 5-HT mediated activation of ERK and induction of LTF when 5-HT is Recently, a new family of neuropeptides was discovered on the C- applied to the cell soma (Ormond et al., 2004). However, the precise terminus of the teneurin type II transmembrane protein. Four peptides from mechanism for the activation of ApTrkl by 5-HT is not clear. First, we each of the teneurins 1-4 were characterized and are called the teneurin C- examined the involvement of a neuropeptide sensorin, which was shown to terminus associated peptides (TCAP). TCAP shares about 20% amino acid be required for activation of ERK and LTF induced by 5-HT (Hu et al., identity to the corticotropin-releasing factor (CRF) family of peptides, and is 2004), on activating ApTrkl and in relation to 5-HT. Second, we extremely well conserved, suggesting an important role in stress and anxiety. overexpressed ApTrkl constructs and examined localization and activation of Behavioural studies indicate that acute intracerebroventricular (ICV) TCAP- the receptor. We hypothesized that 5-HT would cause the trafficking of the 1 modulates anxiety behaviour as measured by acoustic startle. However, the receptor, possibly both internally and externally. Finally, we tested if the specific sites of action of TCAP are still unknown. Therefore, the level of activation of ApTrkl is transactivation through 5-HT G-protein coupled induced c-Fos protein expression was measured by immunohistochemistry to receptors (GPCRs), using adenylyl cyclase (AC)-coupled 5-HT GPCRs determine areas of the brain that respond to central TCAP-1 administration. inhibitor, methiothepin. Male Wistar rats were ICV injected with either saline, TCAP-1, CRF, or co- injected with both TCAP-1 and CRF. Our preliminary results indicate that TCAP may have a modulatory effect on CRF-induced c-Fos expression. This 349 D231 suggests that the TCAP family of peptides may be a novel system that is an ENKEPHALIN IS ALSO EXPRESSED IN GLUTAMATERGIC important regulator of CRF action in the brain. NEURONS OF THE BED NUCLEUS OF THE STRIA TERMINALIS AND THE AMYGDALOID COMPLEX JF, Poulin; Z, Castonguay-Lebel; S, Laforest; G, Drolet. Neurosciences, Universite Laval/Centre Recherche CHUL, Quebec, PQ, Canada HOMEOSTATIC & NEUROENDOCRINE SYSTEMS We recently identified the enkephalin (ENK) innervation of the centromedial amygdala (Poulin et al, JCN 496 :859-876, 2006). We found that ENK fibers in the centromedial amygdala originated mainly from the 351 A301 bed nucleus of the stria terminalis (BST) and others amygdaloid nuclei. ANTI-OBESITY EFFECT OF A NEUTRAL CB1 RECEPTOR However, ENK could colocalize with GABA or glutamate in these structures ANTAGONIST. and this information is essential to the understanding of the anxiolytic effect Adam P. Chambers1*, V. Kiran Vemuri2, Yan Peng2, JodiAnne T. Wood2, of ENK and its physiological relevance in adaptation to stress. This study Quentin J. Pittman1, Alexandros Makriyannis2, Keith A. Sharkey1. aims at assessing the GABA and glutamate phenotype of ENK neurons of the 1Hotchkiss Brain Institute and Institute of Infection, Immunity and BST and amygdaloid complex using double fluorescence in situ Inflammation, Department of Physiology & Biophysics, University of hybridization with combination of riboprobes specific for vesicular Calgary; 2Center for Drug Discovery, Northeastern University, Boston, USA glutamate transporter 1 (VGLUT1) and 2 (VGLUT2), glutamic acid decarboxylase 65 (GAD65), and preproenkephalin (ppENK). We first looked Cannabinoid 1 (CB1) receptor inverse agonists/antagonists potently at the distribution of these genes expression in the divisions of the BST and inhibit food intake in animals and humans, and potentiate emesis in animals. the amygdaloid complex. Although the majority of BST neurons are It is not clear whether these effects result from inverse agonist properties or GABAergic, we observed an important population of neurons expressing from the blockade of endogenous cannabinoid signaling. Here, we examine VGLUT2 in the posterior BST, particularly in the principal, transverse and the effect of a neutral CB1 antagonist, AM4113, on food intake and emesis. inter-fascilular nuclei. Our preliminary results indicate that the posterior BST Neutral antagonist properties were established in HEK293 cells transfected contains two populations of ENK cells, one population expressing GAD65 with human CB1 or CB2 receptors. AM4113 had no effect on forskolin and the other expressing VGLUT2 (principal, transverse and inter-fascilular stimulated cAMP production at concentrations up to 630 nM. The Ki value nuclei). We did not observe any VGLUT2 expression in the anterior BST of AM4113 (0.89±0.44nM) was established in competitive binding assays nuclei nor did we observe VGLUT1 expression in the whole BST. In the with the CB1/2 agonist [3H]CP55,940. AM4113 was 100-fold more selective amygdaloid complex, the expression of VGLUT1 and VGLUT2 is mostly for CB1 over CB2 receptors. We confirmed that AM4113 antagonized CB1 segregated in specific divisions. The expression of VGLUT1 was observed in receptors in vivo by blocking hypothermia induced by CP55,940 (0.3 mg kg- the basolateral (BLA), lateral, as well as in the posterior cortical divisions of 1; i.p., n=5 per group). Food intake was significantly reduced in rats (n=5 per the amygdala. Expression of VGLUT2 was restricted to the medial (MEA), group) treated with AM4113 (10;20 mg kg-1) within 1.5 h of administration basomedial, and anterior cortical divisions (COAa). In the amygdala, more compared with vehicle treated control rats (mean difference from vehicle; - than 95% of ENKergic cells in the BLA expressed VGLUT1 whereas none 14.3;-15.0 g), p<0.05 . Reductions in food intake by AM4113 continued to be of the ENKergic cells of the LA expressed this marker. In addition, there is a significant for 3 d after a single treatment, p<0.05. Reductions in body weight strong colocalization between ppENK and VGLUT2 in the posterior MEA, gain were significant for at least 5 d (-22.5;-34.8 g), p<0.05. The effect of whereas most ENKergic cells in the COAa appear to express GAD65. These chronic treatment with AM4113 on food intake and weight gain in rat is results have broad implications in the functional role of ENKergic currently being investigated. The pro-emetic effect of AM4113 was neurotransmission in the BST and the amygdaloid complex. examined in ferret. AM4113 (5-20 mg kg-1) did not significantly increase vomiting induced by the emetic (M6G; 0.05 mg kg-1 s.c.) compared with vehicle treated ferrets. We show that a centrally active neutral CB1 receptor antagonist shares the appetite suppressant and weight loss effect of inverse

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agonist/antagonists. These data suggest that neutral CB1 receptor antagonists understanding obesity caused by genetic disorders, the complex CNS could be developed into a new class of anti-obesity agents if they display pathways that regulate energy balance, and which are vulnerable to diet- similar properties in humans. based perturbations, remain poorly understood,.as do the mechanisms underlying the changes in the brain resulting in diet-induced obesity. The parvocellular neurons of the hypothalamic paraventricular nucleus (PVN) are 352 A302 one of the primary targets of energy balance-related (i.e., leptin-responsive) SEX DIFFERENCES IN NEURONAL EXPRESSION OF arcuate nucleus (ARC) neurons. ARC projections release orexigenic (NPY, DYNORPHIN AND NEUROKININ B IN THE CONTROL OF AgRP) and anorexic (alpha-MSH, CART) peptides, which we have shown to GONADOTROPIN-RELEASING HORMONE SECRETION IN THE inhibit and potentiate, respectively, GABAergic inputs onto parvocellular SHEEP neurons. To begin to test the hypothesis that diet-induced obesity (DIO) is Guanliang Cheng* (1), Lique M. Coolen (1), Meghan Reale (1), Robert L. accompanied by changes in the response of PVN synapses to energy balance- Goodman (2), Vasantha Padmanabhan (3) and Michael N. Lehman (1). (1) related peptides, we examined responses to different agonists of synaptic Department of Anatomy and Cell Biology, The University of Western inputs in PVN slices from inbred DIO rats maintained on a normal chow diet. Ontario, London (2) Department of Physiology and Pharmacology, West PVN neurons (neurosecretory and preautonomic subpopulations) in inbred Virginia University, Morgantown, West Virginia, USA (3) Reproductive DIO rats expressed electrophysiological properties (membrane potential, Services Program, University of Michigan, Ann Arbor, Michigan, USA input resistance, firing responses) similar to those in outbred Sprague- Dawley rats. However, their sensitivity to both orexigenic (NPY) and The secretion of gonadotropin-releasing hormone (GnRH) into the anorexigenic (MTII) decreased significantly for neurosecretory (NPY: -29.4 pituitary portal blood supply is the final common pathway responsible for vs. -55.8 %, MTII 34.5 vs. 71.9 %), but not preautonomic cells. In addition, neuroendocrine control of reproduction. Prenatal exposure to androgens GABA responses on 25 % of neurons displayed a qualitative change in their causes sexual differentiation of the GnRH system, including its response to MTII, revealing small but reversible inhibition (-23.6 %). These responsiveness to the negative feedback influence of progesterone. A changes were observed in animals taken prior to any significant change in number of neuropeptides, including endogenous opioid peptide, dynorphin body weight. Our data are consistent with a reduction in melanocortin (DYN), and neurokinin B (NKB) have been implicated in mediating these signalling even prior to the onset of obesity in a vulnerable population of feedback effects. Our recent studies in ewe have identified a subset of animals, and may indicate one mechanism of predisposition to obesity. neurons in the arcuate nucleus (ARN) of the hypothalamus that co-express Supported by CIHR operating grants OHN 63278 and MT 10520. WFC is a DYN and NKB. We hypothesize that sex differences in progesterone Medical Scientist of the Alberta Heritage Foundation for Medical Research. negative feedback are due to dimorphism of this neural circuitry. In the present study, we tested this hypothesis by using dual-label immunocytochemistry to compare DYN-positive cells, and their co- 354 A304 expression of nuclear progesterone receptors (PR), in the hypothalami of HOMER-1 IN THE NUCLEUS ACCUMBENS IS INVOLVED IN normal adult rams (n = 4) and ewes (n = 3), and adult ewes that were exposed SEXUAL BEHAVIOR OF MALE RATS to either testosterone (T, n = 4), dihydrotestosterone (DHT, n = 3) or control Joost Wiskerke, Danielle Counotte, Cleusa V.R. de Oliviera, Lique M. (n = 5) treatments during days 30 to 90 of gestation. In addition, we Coolen*. Departments of Physiology & Pharmacology and Anatomy & Cell examined expression of NKB and its colocalization with PR, since NKB in Biology, University of Western Ontario, London the ARN has been previously shown to be sexually dimorphic. Preliminary data from normal sheep revealed significant reductions in the number of Repeated exposure to drugs of abuse induces transcriptional and DYN- and NKB-positive cells (mean 72.1% and 86.2%, respectively) in structural alterations in the mesocorticolimbic system that may contribute to ARN of males compared to females. A very high degree (> 95%) of the development of drug addiction. However, it is largely unknown whether colocalization of DYN and NKB with PR was observed in the ARN of both natural rewarding stimuli cause similar changes in the brain. In animal males and females. Prenatal exposure to androgens also resulted in models, sexual behavior, and in particular ejaculation, is reinforcing and significant reductions in the number of DYN- and NKB-positive cells in the highly rewarding, but does not lead to compulsive behavior, in contrast to ARN of both T- and DHT-treated animals compared to control ewes. Sex and drugs of abuse. Therefore, our lab recently set out to study sex-induced prenatal androgen-induced differences in peptide cell number were transcriptional and structural changes in male rats. These experiments regionally limited to the middle and caudal divisions of the ARN, sites of the confirm that sexual behavior induces such alterations within the majority of DYN and NKB cells. In summary, neuronal expression of both mesocorticolimbic system. One of the most pronounced sex-induced DYN and NKB is sexually dimorphic in the ARN of the adult sheep, and is transcriptional changes within the nucleus accumbens (NAcc) is an up- likely due to the organizational influence of prenatal androgens. Differences regulation of Homer-1 (+200-420%), a scaffolding protein located in the in DYN and NKB cell number between male and female hypothalami is postsynaptic density that has been implicated in the regulation of signal consistent with sex differences in responsiveness to progesterone negative transduction, synaptogenesis, receptor trafficking, and regulation and feedback, and provide further support for the role of this neuronal maintenance of extracellular glutamate levels. There are two main splice subpopulation in controlling pulsatile GnRH secretion. The ability of both T variants of Homer-1, the immediate early gene (IEG)-like Homer-1a and DHT to decrease the number of DYN/NKB cells suggests that (~25kDa) and the constitutively expressed Homer-1b/c (45-47kDa), which differentiation of this circuitry is due to exposure to prenatal androgens and compete for the same binding sites and have opposing functions. Using real not estrogen (Supported by HD39916 to MNL and NIH HD41098 to VP). time PCR, we here confirmed that both acute sexual activity and sexual experience induced an up-regulation of Homer-1b/c. Next, we studied the functional significance of that up-regulation using antisense oligonucleotides 353 A303 (AS) to Homer-1 to down-regulate both Homer-1a and 1b/c proteins within ALTERATIONS IN PVN PARVOCELLULAR NEURONS the NAcc. We used two different Homer-1 AS sequences, which previously RESPONSES TO NPY AND MELANOCORTINS IN AN INBRED have been shown to down-regulate Homer-1 protein by ~35% (Ghasemzadeh RAT MODEL SUSCEPTIBLE TO DIET-INDUCED OBESITY (DIO) M.B. et al. 2003). Results show that continuous infusion of Homer-1 AS into Igor V. Melnick*, Nina Pronchuk and William F. Colmers. Department of the NAcc of male Sprague Dawley rats for 9-11 days severely inhibited Pharmacology, University of Alberta, Edmonton sexual behavior. Specifically, a lower percentage of the AS animals displayed mounts, intromissions, and ejaculation as compared to control animals. Neurons of the mediobasal hypothalamus are intimately involved in Moreover, latencies to mount, intromission, and ejaculation were longer in energy homeostasis. While considerable progress has been made in

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the AS animals as compared to control animals. In contrast, novelty-induced gene and 9 SNPs in the NPY gene; the SNPs are relatively evenly distributed locomotor activity was not affected by antisense treatment, indicating no in the regions covered. Three haplotype blocks were detected, one CRH effect on general activity. These findings suggest that Homer-1 in the NAcc block capturing 4 CRH SNPs and 2 NPY blocks, each involving two NPY is essential for the initiation of sexual behavior in male rats, possibly via its SNPs. An association between one intronic NPY SNP and the behavioral role in regulating proper glutamatergic input to the NAcc. Supported by NIH response to novelty “defensive aggression” was detected. DA14591 to LMC. These results are coherent with other reports implicating NPY in defensive aggressive behavior, and support the notion that fear responses are fundamental behavioral traits for the dissection of anxiety. 355 A305 INDIVIDUAL DIFFERENCES IN ANXIETY-LIKE BEHAVIOUR ARE REVERSED BY VARIATIONS IN MATERNAL CARE 357 A307 Sabine K. Dhir*, Carine Parent, Michael J. Meaney. Douglas Hospital ACTIVATION OF ESTROGEN RECEPTOR β IN PRIMARY Research Center, McGill University, Montreal RAT HYPOTHALAMIC NEURONS INCREASES NITRIC OXIDE PRODUCTION THROUGH nNOS PHOSPHORYLATION Natural variations in maternal care influence physiological responses to Sarah Gingerich* and Teresa Krukoff. Centre for Neuroscience and stress and emotional events. Previously we have shown that the adult male Department of Cell Biology, University of Alberta, Edmonton offspring of Low Licking and Grooming (LG) mothers show increased anxiety levels when tested for time spent in the center of a novel field. In We have recently shown in vivo that nitric oxide (NO) in the this study we investigated the effect of maternal rearing on novelty induced paraventricular nucleus (PVN) of the hypothalamus mediates estrogen’s anxiety in cross fostered animals to determine whether maternal care can effects on blood pressure responses to L-glutamate stimulation. We have also reverse/alter both a behavioral phenotype in later life. Partial litters of High shown that estrogen modulates the expression of neuronal nitric oxide LG or Low LG dams were cross fostered on post natal day 0 to dams of the synthase (nNOS) in the PVN of hypothalamic slice cultures and increases alternate phenotype or the same phenotype while un-fostered littermates NO production from neuroblastoma cells. Although NO is an important were used as control subjects. The results indicate that it is the level of mediator of estrogen actions in neurons of the PVN, little is known about the maternal LG demonstrated by the dam which predicts center time in the open mechanism(s) of estrogen’s effects on NO. Furthermore, because we have field test in adult male offspring. Biological offspring of High LG dams shown that estrogen acts through estrogen receptor β (ERβ) to reared by Low LG mothers were significantly more fearful in the novel field affect the NO system in the PVN, we were interested in identifying the compared to both offspring of High LG mothers reared by a foster High LG signaling mechanisms activated by ERβ to affect NO in these cells. mother, and the High LG offspring control group. The reciprocal was true for nNOS catalyzes NO production in neurons and it has been shown that biological offspring of Low LG dams reared by High LG mothers. These phosphorylation of nNOSser847 or nNOSser1416 leads to decreases or results suggest that maternal care is a fundamental determinant of anxiety increases in nNOS activity, respectively. Therefore, we tested the hypothesis which can be reversed by cross fostering in early life. that activation of ERβ in neurons increases NO production by increasing nNOS activity through the modulation of nNOSser847 and nNOSser1416 phosphorylation. Primary hypothalamic neurons from E17 356 A306 rats, grown for 8-9 days in vitro, were treated for 5 minutes with the selective DISSECTING ANXIETY IN THE VERVET MONKEY: A SEARCH ERβ agonist, diarylpropionitrile (DPN, 10 -1000 nM). NO production FOR ASSOCIATION BETWEEN POLYMORPHISMS IN THE CRH was then measured using the 2,3- diaminonaphthalene nitrite assay and AND NPY GENES AND ANXIOUS BEHAVIOR changes in nNOS phosphorylation were determined by western blot analysis. Martine Elbejjani 1, Frank R. Ervin 2,4, Caroline Desbiolles 3 and Roberta Using immunofluorescence we found that at least 90% of cultured M. Palmour 1,2,4.. Departments of Human Genetics 1, Psychiatry 2 and hypothalamic neurons expressed ERβ and that more than 50% of Biology 3, McGill University, Montreal; Behavioral Science Foundation 4, neurons expressed nNOS. DPN (10 nM) increased NO production by 38%, St-Kitts decreased nNOSser847 phosphorylation by 38%, and increased NOSser1416 phosphorylation by 56%. Together, these results suggest that activation of The implication of corticotropin- releasing hormone (CRH ) and ERβ stimulates nNOS activity. Finally, because estrogen has been neuropeptide Y (NPY) in the pathophysiology of anxiety and anxiety-related shown to activate the steroid receptor co-activator (Src) pathway in disorders is well established. Stress response and anxiety are mediated, at endothelial cells, we determined whether stimulation of ERβ in least in part, by CRH, a regulator of the hypothalamic-pituitary-adrenal neurons activates Src. We found that DPN (10 nM) increased SrcTyr416 pathway. Biological functions of NPY include the regulation of the stress phosphorylation by 64%, suggesting that the Src signaling pathway is response (by regulating the release of hypothalamic hormones including activated by ERβ stimulation in neurons. Our findings suggest that CRH), appetitive behaviors and emotional behavior. The objective of this activation of ERβ in hypothalamic neurons increases NO production study is to explore the genetic variations in CRH and NPY genes in a well- through phosphorylation of nNOS and that activation of the Src kinase documented behavioral animal model, the vervet monkey (Chlorocebus pathway likely plays a role in this effect. aethiops sabaeus), in order to uncover a possible association between these polymorphisms and anxious behavior. The anxious behavior is assessed through a behavioral phenotype, based on observational and quantitative 358 A308 evaluation of the reactivity of 4 birth cohorts of vervet monkeys (n=167), SUSTAINED SODIUM DEPLETION INDUCES A REVERSIBLE during late infancy and adolescence, in both social and novel settings. The PLASTICITY OF THE MU-OR RESPONSE IN THE MEDIAN vervet CRH and NPY genes have been amplified and sequenced; the priority PREOPTIC NUCLEUS was given to the regions expanding from -1kb upstream of the transcription Mélaine Henry*, Guy Drolet and Didier Mouginot. Centre de recherche du initiation site through the second exon. The sequences cover the promoter CHUL (CHUQ), Neuroscience, Université Laval, Québec fragments where most of the regulatory elements are found in both genes and the regions containing polymorphisms that have been associated with Salt appetite is a behavioral response to sodium (Na+) loss in the anxious traits in both humans and non-human primates. Polymorphism organism and there is growing evidences that the opioid system seems to play discovery analysis (using NovoSNP and Phred Phrap) revealed the presence a significant role in the motivated aspect of salt intake. Since the median of a deletion and an insertion in the promoter of CRH, 8 SNPs in the CRH preoptic nucleus (MnPO) appears as an essential interface between central Na+ detection and induction of Na+ intake, the goal of the present study was

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to determine whether the excitability of the MnPO neurons was modulated 360 A310 by the µ opioid receptor agonist DAMGO and whether the DAMGO- NESFATIN-1 MODULATES THE EXCITABILITY OF NEURONS IN mediated response(s) was modified by a sustained Na+ depletion, which THE PARAVENTRICULAR NUCLEUS OF THE HYPOTHALAMUS generates salt appetite. The experimental model of sustained Na+ depletion Ted D. Hoyda1, Christopher Price1, Willis K. Samson2 and Alastair V. consisted in two subcutaneous injections of furosemide (10 mg/kg) followed Ferguson1. 1Department of Physiology, Queen’s University, Kingston, by a free Na+ diet (0.03% NaCl) for 20h and ad libidum access to clear water. 2Department of Pharmacological and Physiological Science, Saint Louis The electrophysiological recordings were performed with the patch-clamp University, St. Louis, USA technique. Our results indicate that DAMGO triggered two distinct responses in the MnPO neurons. (1) In 25 % of the neurons, DAMGO reduced the Nesfatin-1 is a newly discovered satiety molecule produced in the amplitude of EPSCs evoked by electrical stimulation of the SFO by 52 ± appetite control centers of the hypothalamus including the lateral 13%. This inhibitory effect was mediated by presynaptic µOR. The hypothalamic area, the arcuate, the supraoptic and the paraventricular DAMGO-mediated reduction in glutamatergic transmission was not affected nucleus (PVN). Through an unidentified mechanism acute by the sustained Na+ depletion. (2) In 41% of the neurons, DAMGO intracerebroventricular injections of nesfatin-1 dose dependently inhibit triggered a membrane hyperpolarization (11.4 ± 0.6 mV) that was mediated feeding while chronic injections reduce body weight. Using acutely prepared by postsynaptic µOR. Interestingly, sustained Na+ depletion extended the hypothalamic slices we have investigated the effects of nesfatin-1 neuronal population hyperpolarized by DAMGO to 60% without affecting administration on the membrane properties of PVN neurons through current- the amplitude of the hyperpolarization. The population sensitive to DAMGO clamp recordings. The majority of neurons examined hyperpolarized in returned to 39% 24h after Na+ repletion. It is worth noting that 70% of the response to 10 nM nesfatin-1 (-7.6 ± 1.4 mV, 13/21) while others depolarized neurons hyperpolarized by DAMGO under the two Na+ conditions were (6.3 ± 1.0 mV, 3/21) or did not respond (5/21). Additionally neurons which identified as Na+-sensing neurons. The present study indicates that the hyperpolarized showed one of two response profiles: a continuous excitability of MnPO neurons including a majority of Na+-sensors is reduced hyperpolarization which reaches a maximum and then recovers (8/13) or the by enkephalin peptides. Together with hyponatremia-induced induction of a slow wave oscillation in the membrane potential (5/13). These hyperpolarization of the Na+-sensors, our results highlight the fact that data are the first to demonstrate the effects of nesfatin-1 on the excitability of humoral and neural sensory informations signaling for hyponatremia are PVN neurons and thus further highlight the PVN as a potential target where coherently integrated within the MnPO. This study suggests that enkephalin nesfatin-1 exerts its effects on feeding behavior. peptides may play an important role not only in the motivated aspect of salt intake, but also in the regulation of central detection/integration of Na+ changes. Source of Research Fund: Supported by CIHR and Heart and Stroke 361 C301 Foundation (Québec). Didier Mouginot is a FRSQ scholar. ACUTE STARVATION ALTERS THE FEVER RESPONSE TO LIPOPOLYSACCHARIDE IN RATS *Wataru Inoue and Giamal N. Luheshi. Douglas Hospital Research Centre, 359 A309 Department of Psychiatry, McGill University, Montreal NOCICEPTIN/ORPHANIN FQ INDUCES IRREVERSIBLE ACTIVATION OF GIRK CHANNELS IN OREXIN NEURONS Insufficient energy supply, such as that experienced under starvation, can Michiru Hirasawa* and Matthew P. Parsons. Division of Basic Medical cause a number of physiological changes including suppression of immunity Sciences, Memorial University and decrease in thermogeneis exemplified by a reduction in fever response to exogenous pathogens. The underlying mechanisms regulating this alteration Nociceptin/orphanin FQ (N/OFQ) is an opioid-like peptide known to act of fever are not clear and whether the mediators of fever (cytokines) are as a functional “anti-opioid” because it opposes the effects of opioids on the involved has not been investigated in depth. The aims of the present study activity of the mesolimbic pathway as well as nociception. Orexin neurons therefore were 1) to confirm that starvation attenuates the fever response to located exclusively in the lateral hypothalamus/perifornical area (LH/PFA) LPS, an exogenous pyrogen and a potent activator of cytokines, 2) to have known projections to the ventral tegmental area (VTA) where they characterize the plasma cytokine levels following LPS injection, 3) to exhibit an excitatory effect on dopamine neuron activity and subsequent investigate the expression levels of brain IL-1β and COX-2, important dopamine release in the nucleus accumbens and prefrontal cortex. As it has regulators of the central response in fever generation. Adult female rats were been shown that the N/OFQ peptide (NOP) receptor is expressed in the fasted for 48 h following which they received a single intraperitoneal LH/PFA, we hypothesized that the inhibitory action of N/OFQ on the injection of LPS (100 µg/kg) or sterile saline. Over the period of fasting (48h) mesolimbic pathway is at least partially due to inhibition of orexin neurons. the baseline body temperatures was lower in fasted rats as compared to the To test this, whole-cell patch clamp recordings were preformed on orexin ad lib fed group (36.5 ± 0.3 vs. 37.4 ± 0.1 C°). Saline injection caused a neurons using acute hypothalamic slices obtained from male SD rats. We transient stress-induced hyperthermia in both groups reaching a similar peak found that 2-5 min application of N/OFQ (0.1 – 1microM) induced an temperature (37.6 ± 0.4 vs. 37.8 ± 0.3 C°) indicating that the thermogenic irreversible, sustained outward current that lasted up to 80 min. N/OFQ effect ability is preserved in the fasted animals. Both fasted and fed rats responded was blocked NOP receptor antagonist UFP101, but not the broad spectrum to LPS with an initial hypothermia followed by an increase in body opioid receptor antagonist naloxone. However, once the effect was induced, temperature. However, the fasted animals showed bigger hypothermia (36.1 UFP101 was unable to reverse the effect. Therefore, the induction of the ± 0.2 vs. 36.7 ± 0.2 C°) and smaller fever (38.2 ± 0.2 vs. 38.9 ± 0.2 C°) as effect required N/OFQ binding to NOP receptors but the maintenance was compared with the fed group. In a separate study, plasma cytokine levels and independent of ligand binding. The N/OFQ-induced current reversed at the brain gene expressions were measured 2 h after injection of LPS or saline. potassium reversal potential, and was sensitive to Ba2+. Furthermore, the Both fasted and fed animals responded to LPS with a dramatic increase in the effect was abolished when GDPbetaS was included in the internal solution. plasma levels of TNFα and IL-6 as compared with the saline-treated These results suggest that N/OFQ irreversibly activates GIRK channels in group. The fasted animals however had significantly lower TNFα orexin neurons. Ba2+ had no effect on its own, indicating that there is no levels than the fed group (1.6 ± 0.6 vs. 3.8 ± 1.2 ng/ml), whereas constitutive activity of GIRK channels in basal condition. In current clamp interestingly, IL-6 levels were similar in both fasted and fed rats (4.1 ± 0.9 mode, N/OFQ induces a persistent hyperpolarization and cessation of firing vs. 3.1 ± 0.5 ng/ml). In the brain, LPS increased the expression of IL- activity. In conclusion, our study demonstrates that N/OFQ causes a tonic 1β and COX-2 mRNAs to a similar magnitude in both fasted and fed suppression of orexin neurons. This may in turn reduce the excitatory animals. These results demonstrate that acute starvation attenuates the fever influence of orexins on the VTA and tone down the activity of the reward response in rats and that this alteration is accompanied with attenuated circuit. Supported by CIHR and NSERC.

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production of TNFα but not IL-6. Surprisingly, given the attenuated 364 C304 fever, neither COX-2 nor IL-1β expressions was affected by fasting. DEVELOPMENT OF THE ADRENOCORTICAL STRESS RESPONSE IN ARTIFICIALLY REARED RAT PUPS Anna M. Lomanowska and Gary W. Kraemer. Department of Psychology, 362 C302 University of Toronto at Mississauga THE EFFECT OF PACED COPULATION AND STRAIN CONDITIONING ON THE DEVELOPMENT OF PARTNER Prolonged maternal separation has been consistently shown to have long- PREFERENCE IN MALE RATS term consequences on the neural and behavioural development of infant rats. N. Ismail, S.L. Jones, M.D. Graham, M. Georgescu & J.G. Pfaus. Studies suggest that these effects are mediated through the sensitization of CSBN/Psychology, Concordia University, Montréal the developing stress response system. Complete deprivation of maternal care, by way of artificial rearing, leads to comparable neural and behavioural Although male rats are believed to show greater sexual arousal and changes in later-life, but little is known about the effects of this procedure on mating preference for a novel female compared to a familiar one, we have the development of the stress response system. To investigate the shown that after repeated copulation to ejaculation with a female bearing a adrenocortical response to stress during artificial rearing of rat pups, basal neutral odor in pacing chambers bisected by a 1-hole divider, male rats and stress induced levels of the hormone corticosterone (CORT) were display a conditioned ejaculatory preference for a female bearing the odor measured on post-natal day (PND) 6 and 12. Two types of stressors were relative to a female not bearing the odor. The aim of the present study was to used: an intraperitoneal injection of saline on PND 6 and 3 hrs of food examine if males might develop an ejaculatory preference for a familiar deprivation on PND 12. To assess the physiological impact of artificial female of the same or different strain after repeated copulation with the same rearing and exposure to stressors, blood glucose was also measured. In PND female in a pacing chamber bisected by either a 1-hole or 4-hole divider. In 6 pups, there were no differences between basal and injection stress induced this experiment, male Long-Evans rats were given 10 copulatory trials with levels of either CORT or glucose. In PND 12 pups, food deprivation stress the same Long Evans or Wistar female in either the 1-hole or 4-hole resulted in an increase in CORT levels in both artificially and maternally condition. Copulatory preferences were then examined in an open field reared groups, and a corresponding decrease in glucose levels. Surprisingly, where the males had the choice to copulate with either the familiar female or there were no differences between artificially and maternally reared rats in a novel female of the same or other strain. Results indicated that males basal or stress induced levels of CORT or glucose on either PND. These trained in the 1-hole condition with the same Long Evans female displayed a findings suggest that, unlike maternal separation, artificial rearing does not conditioned ejaculatory preference for the familiar vs. novel female. lead to a sensitization of the adrenocortical stress response in rat pups. Thus, However, males trained in the 1-hole condition with the same Wistar female the effects of artificial rearing on neural development and later-life at every trial copulated indiscriminately with the familiar and novel females. behavioural functioning may be mediated through other mechanisms. No preference was detected in males trained in the 4-hole condition. These findings suggest that males display an ejaculatory preference for strain cues if the familiar female is of their own strain following training in a 1-hole 365 C305 paced copulation condition. Supported by CIHR to JGP. SIMULATION OF VASOPRESSIN RELEASE IN A QUANTITATIVE MODEL OF HYDROMINERAL HOMEOSTASIS *Louis Nadeau, Didier Mouginot. Unité de Neuroscience, Centre de 363 C303 recherche du CHUL, Université Laval SEXUAL BEHAVIOR IN AGED ACYCLIC FEMALE RATS S.L. Jones & J.G. Pfaus. CSBN/Psychology, Concordia University, Montréal Vasopressin is the antidiuretic hormone that is released in the general blood circulation when plasma tonicity is elevated. The release of Normally cycling female rats display a cell cycle pattern of estrus, vasopressin from axon terminals of magnocellular neurons (MCNs) is highly proestrus, metestrus and diestrus, occuring over 4-5 days, as determined by regulated and is achieved during depolarization of the MCNs. The change in vaginal smears, and are receptive during the proestrus and estrus phases. As MCN excitability is mediated by the intrinsic property of the MCNs the female ages, the cycles become irregular, eventually leading to persistent (osmoreceptors) and by their integration of synaptic signals as they belong to estrus (PE) and finally anestrus. Many of the neuroendocrine fluctuations a hydromineral neuronal network. In the context of creating a computational that occur during this transition have been studied, however these changes model of that hypothalamic neuronal network controlling vasopressin have not been fully investigated with respect to sexual behavior. The present release, the goal of the present study was to design a physiologically realistic study observed the vaginal smears of nineteen acyclic female Wistar rats (age test-bed that mimicked the MCNs and kidney dynamic in response to a >15 months) over a 15-day period to confirm irregular cyclicity, and females plasma osmotic challenge. This model is implemented in Scicos, a module of were subsequently subjected to sexual behavioral testing in bi-level the Scilab software. Currently, the model is at a high level and contains three chambers with sexually experienced Long-Evans males. 84% of the females distinct interconnected objects : the “plasma”, the “kidneys” and the had estrus or proestrus vaginal cytology on the test day. Of those females, “hypothalamic hydromineral network”. Those objects are modeled with 94% expressed defensive behaviors, 68% received a mount, 68% performed particular mathematical functions that have been implemented with olfactory investigations on the male, 63% expressed level changes, 53% physiological parameters collected from a thorough analysis of the displayed hops and darts, 44% showed aggressive behaviors and 38% appropriate literature. The test-bed functions as following: the object showed a lordosis of at least magnitude 1. None of the females received an “plasma” contains three distinct informations: the plasma volume (ml), the ejaculation from the male, presumably because of their defensive and plasma vasopressin (pg) and the plasma Na+ (mmol). All these parameters rejection responses. This pattern of data is strikingly similar to what is found represent the chemosensory signals. The object “hypothalamic hydromineral in female rats during estrus termination, in which females drop out of heat network” represents the integrator and it dynamically adjusts the secretion of following repeated vaginocervical stimulation. These findings suggest a vasopressin after having analyzed the chemosensory signals. It also activates similar inhibitory mechanism may be involved in the two states and leads to a drinking response when needed. Finally, the object “kidneys” represents the reduction or absence of female appetitive and consummatory female sexual effector by adjusting urine volume and Na+ concentration in order to restore behaviors. Furthermore, these results suggest that decreased sexual the plasma to the osmotic set-point. Despite its apparent simplicity, the responsiveness occurs prior to changes in vaginal cell morphology in presented model works within the biological limits to mimic the dynamic response to irregular ovarian hormone output. Supported by CIHR and changes in the plasma, vasopressin release and urine content occurring NSERC to JGP. during a hyperosmotic challenge. This model represents therefore a realistic test-bed for a computational model of the hydromineral network.

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366 C306 368 C308 IMPACT OF GUT MICROFLORA ON LEARNING, BEHAVIOUR IL-6 AND LEPTIN DIFFERENTIALLY ACTIVATE STAT3 AND THE AND CENTRAL NERVOUS SYSTEM GENE EXPRESSION COX2-MPGES-PATHWAY IN THE BRAIN DURING LPS-INDUCED Neufeld, K.A. *, Bienenstock, J., Foster, J.A. Brain-Body Institute, St. SYSTEMIC INFLAMMATION Joseph's Healthcare. Department of Psychiatry & Behavioural Christoph Rummel1, Christelle Sachot1, Wataru Inoue1, Stephen Poole2 and Neurosciences, McMaster University Giamal N. Luheshi1. 1Douglas Hospital Research Centre, Department of Psychiatry, McGill University, Montreal, 2Department of Endocrinology, Germ-free mice have no intestinal microflora and thus exhibit an National Institute for Biological Standards and Control, Potters Bar, EN6 undeveloped immune system. Previous work has demonstrated that in 3QG, United Kingdom conjunction with these gastrointestinal and immune deficits, germ-free mice exhibit an altered central nervous system (CNS). Specifically, when Systemic inflammatory insults result in CNS mediated sickness like compared to conventional animals with normal gut flora, germ-free mice symptoms including fever and anorexia. Signaling pathways regulating these demonstrate an altered hypothalamic-pituitary-adrenal (HPA) stress axis, responses involve a multitude of immune mediators belonging largely to the with increased corticosterone and adrenocorticotropin hormone (ACTH) ‘cytokine’ family. Among those, IL-6 plays a major role. Recently, leptin, an released in response to restraint stress. Additionally, they show decreased adipose-derived hormone known to regulate appetite and energy balance, has hippocampal protein levels of brain derived neurotrophic factor (BDNF), and also emerged as a mediator of inflammation. To address the relative decreased NMDA receptor subunit NR-2A mRNA levels. To date, no studies contribution of IL-6 and leptin as mediators in immune-to-brain examining the behavioural phenotype of the germ-free mouse have been communication, the activation of brain cells during lipopolysaccharide conducted. As both BDNF and NR-2A are molecules key to hippocampal- (LPS)-induced systemic inflammation was assessed. In order to differentiate dependent learning and plasticity, we hypothesized that the germ-free between activities resulting from the action of IL-6 from that of leptin, both animals would show learning deficits specific to the hippocampus. Our of which signal through STAT3, IL-6 knockout (IL-6KO) mice were used. results demonstrate that unstressed germ-free mice show basal deficits in Wild type and IL-6KO mice were injected with a moderate dose of LPS (50 contextual learning when compared to conventional animals. In addition, μg/kg, i.p.) and STAT3 activation in the brain assessed by they exhibit basal learning deficits in the elevated plus maze (EPM). immunohistochemistry. The majority of STAT3 activation located primarily Through in situ hybridization experiments we are currently examining the in endothelial cells throughout the brain appeared to be IL-6 mediated. Using mRNA levels of key molecules in hippocampal-dependent learning and HPA RT-PCR we show that LPS-induced upregulation of mRNA expression of the axis functioning. Our future work aims to examine the impact of specific suppressor of cytokine signaling 3 (SOCS3), a marker of STAT3 activation immune deficits on the development and function of the CNS. was significantly reduced but not abolished in the hypothalami of KO animals. This was accompanied by a reduction in cyclooxygenase (COX)2 and microsomal prostaglandin E synthase (mPGES), the rate limiting 367 C307 enzymes for synthesis of PGE2, an important mediator in brain derived NEUROPEPTIDE W HAS COMPLEX EFFECTS ON THE sickness responses. In these mice we observed LPS-induced STAT3- MEMBRANE POTENTIAL OF ARCUATE NUCLEUS activation in the organum vasculosum of the lamina terminalis, the SOMATOSTATIN NEURONS supraoptic nucleus, the raphe pallidus nucleus and in meningial cells and C.J. Price, W.K. Samson and A.V. Ferguson. Department of Physiology, distinct large blood vessels throughout the brain. The LPS induced response Queen's University, Pharmacological and Physiological Science, Saint Louis in these specific brain structures was drastically reduced in the KO animals University School of Medicine in the presence of a mouse leptin-antiserum, which also significantly inhibited the upregulation of mRNA expression of SOCS3 and COX2 but Somatostatin neurons in the hypothalamic arcuate nucleus help to interestingly not mPGES in the hypothalamus. In conclusion, these regulate the release of growth hormone. Intracerebroventricular observations confirm that the role of IL-6 in immune-to-brain administration of the peptide neuropeptide W (NPW) results in lowered communication in LPS-induced systemic inflammation involves the plasma growth hormone but has no direct effect on growth hormone release activation of the STAT3-COX2-mPGES-pathway in the brain. The from somatotropes. Therefore using a combination of whole cell patch contribution of leptin to this response appears to be limited to distinct areas clamp recording from hypothalamic brain slices containing the arcuate of the brain/cell types and does not appear to involve mPGES induction. nucleus and single-cell reverse transcriptase polymerase chain reaction we have characterized the response of arcuate somatostatin neurons to NPW. In current clamp recordings neurons mainly depolarized when exposed to 369 C309 nanomolar concentrations of NPW. However, some neurons hyperpolarized CELL SURFACE REMODELING AND THE MEMBRANE or showed a mixed depolarization-hyperpolarization. When arcuate neurons SKELETON IN OSMOTICALLY PERTURBED MAMMALIAN were pre-treated with the voltage-gated sodium channel blocker TTX, the NEURONS depolarizing effect of NPW was largely inhibited while the slowly Natalya Shulyakova,1,2* Jun A Wang3 , Catherine E Morris 3 and Linda R developing hyperpolarization was preserved. Likewise in the presence of the Mills.1,2. Toronto Western Hospital, Cellular and Molecular Division, UHN, ionotropic glutamate receptor antagonists APV and DNQX depolarizing and Department of Physiology, University of Toronto1,2 Nurosciences, responses were inhibited. Therefore somatostatin neurons in the arcuate Ottawa Health Research Institute, Ottawa3 nucleus are mainly depolarized by NPW, through a mechanism that involves the elevation of glutamatergic synaptic drive onto the neurons. In addition Neuronal surface area regulation (SAR) is the homeostatic process by somatostain neurons are directly hyperpolarized by NPW. which neurons reorganize their plasma membrane during swelling and shrinking. Membrane recruited to the surface during swelling is retrieved during shrinking, generating transient vacuole–like dilations (VLDs) at the adherent surface. Previous studies in molluscan neurons show that VLD formation and VLD recovery is characterized by the easily detectable reorganization of the actin-spectrin membrane skeleton around VLDs. Here we extend these studies on cell surface remodeling to mammalian neurons. In PC12 neurons VLD formation and recovery was associated with dynamic changes in F-actin. On collagen the half-time for VLD recovery was 3 min

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versus 20 min on a more adhesive substrate, poly-L-ornithine. In cells treated regeneration. Current evidence points to a multicomponent receptor complex with reagents that interfere with actin and myosin (cytochalasin B, comprised of p75NTR, NgR and Lingo-1 that responds to these myelin- latrunculin A, and N-ethylmaleimide), F-actin did not associate with VLD associated inhibitors and transduces the inhibitory signal to the neuron. We membranes and VLD recovery was delayed or blocked. In PC12 neurons have identified a protein, termed LGI1 that interacts with components of the spectrin is also associated with VLD membranes. Reagents that interfere with myelin-associated inhibitor receptor complex and functions to antagonize the spectrin remodeling (calpeptin, MDL-28170) did not prevent the F- growth inhibitory effects of myelin. We will present data concerning our actin/VLD association, but did impair VLD recovery. Oxygen-glucose identification of LGI1 as a myelin-based growth inhibitor antagonist, and deprivation did not prevent VLD recovery in PC12 neurons or in discuss avenues we are exploring to determine how LGI1 mediates this hippocampal neurons. In PC12 neurons subjected to severe ATP depletion, F- effect. actin associated with VLD membranes but was non-contractile and VLD recovery was blocked. Recovery resumed upon restoration of energy metabolism. 372 A402 These results indicate that mammalian neurons demonstrate robust SAR THE PARAVENTRICULAR NUCLEUS OF THE THALAMUS AS A and that VLD formation and VLD recovery are differentially affected by REGULATOR OF TONIC DOPAMINE LEVELS IN THE NUCLEUS agents that disrupt the membrane skeleton. VLD formation is resistant to ACCUMBENS severe ATP depletion, myosin inhibition and depolymerization of F-actin. In Kirouac, G.J., Parsons, M,P., and Li, S. Dept. of Oral Biology, Faculty of contrast to VLD recovery is sensitive to ATP depletion, disruption of actin Dentistry, University of Manitoba, Winnipeg polymerization, disruption of existing F-actin pools and inhibition of myosin ATPase. The shell of the nucleus accumbens (NacSh) is strongly innervated by dopamine (DA) neurons in the ventral tegmental area (VTA) and glutamate neurons in the paraventricular nucleus of the thalamus (PVT). The present in 370 C310 vivo voltammetry study examined if electrical stimulation of the PVT evoked DAYTIME SLEEPINESS IS IT RELATED TO THE DA release in the NacSh of urethane anesthetized rats. Stimulation of the PREMENSTRUAL SYNDROME IN STUDENTS? PVT (40 Hz, 1.0 ms, 400 µA, 5s) resulted in a brief increase in the *Mouna Zerradi*, *Ikram Bachraoui*and *Rachida Roky* electrochemical current detected in the NacSh. Inhibition of dopamine uptake (GBR 12909, 10 mg/kg i.p.) increased the magnitude of the evoked Diurnal somnolence is a frequent phenomenon in the young people. It response while inhibition of serotonin (clomipramine, 10 mg/kg i.p.) or could have an impact on the cognitive performances in the university norepinephrine uptake (desipramine, 10 mg/kg, i.p.) had no effect on the students. Girls were reported to present more daytime sleepiness than boys. PVT-evoked responses. Blocking of ionotropic glutamate receptors in the The premenstrual syndrome (PMS) is often accompanied by some psychic NacSh with local administration of kynurenic acid (50 nM, 500 nl over 3 syndromes, which could be related to diurnal somnolence in the girls. min) attenuated the PVT-evoked responses. In contrast, removal of the Objectives of the study: to determine the relationship between the diurnal influence from DA neurons in the VTA with 4% lidocaine (500 nl injected in somnolence and the premenstrual syndrome in the girls. A sample of 407 the medial forebrain bundle) or apomorphine (0.15 mg/kg; i.v.) had no effect. students, including 172 of men and 235 of women, filled out the Epworth Stimulation of the PVT for a longer period (mins) at lower current intensity sleepiness scale (ESS). The girls filled out a questionnaire on the (10 Hz) produced an increase in dopamine oxidation current which was time- premenstrual syndrome (PMS). The sleepiness score of girls was more locked with the stimulation. This study suggests that glutamate release from elevated than that of boys (p=0.0002). Girls also slept (p=0.0001) and woke PVT terminals can act on glutamate receptors in the NacSh to induce DA up (p=0, 0001) earlier than boys and presented a longer night time sleep efflux. Since the PVT is activated by arousal and stress, we propose that the duration (p=0.038). The comparative analysis showed that the scores of the PVT modulates arousal state and tonic levels of DA in the NacSh. PMS presented a significant (P <0.008) relationship with the scores of sleepiness. Indeed, the ESS is higher in the girls who presented the extreme syndromes of the PMS (ESS= 10.26) in comparison with those who had less 373 A403 severe symptoms (ESS = 9.31, p=0.0406), or moderate (ESS = 9.05, APOLIPOPROTEIN E GENOTYPE AND CONCUSSION IN p=0.0079). The sleep deprivation did not seem to explain the higher VARSITYATHLETES: A PROSPECTIVE COHORT STUDY sleepiness scores in girls, since the preferred sleep duration is not higher in *Kristman VL (1,2), Kreiger, N (2,3), Tator, CH (1,4), Mainwaring, L (5), the girls. Conclusion: Diurnal somnolence in girls was related to the PMS. Richards, D (5,6), Jaglal, S (2,7), Tomlinson, G (2,8). 1 Toronto Western One of the perspectives of this study is to determine the attenuating factors Research Institute, University Health Network 2 Department of Public of diurnal sleepiness. Health Sciences, University of Toronto 3 Cancer Care Ontario 4 Division of Neurosurgery, Department of Surgery, University of Toronto 5 Faculty of Physical Education and Health, University of Toronto; 6 Toronto Rehabilitation Institute; 7 Department of Physical Therapy, University of OTHER Toronto; 8 Toronto General Research Institute, University Health Network

Concussion is a common sport-related injury and it is hypothesized that 371 A401 possession of an epsilon-4 allele in the apolipoprotein E gene (APOEe4) may LGI1 IS A NOVEL ANTAGONIST OF MYELIN-BASED GROWTH increase concussion risk. Understanding the association between APOEe4 INHIBITORS and concussion would be useful for developing prevention strategies targeted Kristy Favell*, Rhalena Thomas*, Jose Morante-Redolat*, Melissa Wright, to APOEe4 carriers. To determine the association between possession of an Isabel Rambaldi, Sebastien Paris, Yves Durocher, Alyson Fournier, Jordi APOEe4 allele and concussion. A prospective cohort study was conducted Perez-Tur, Philip A Barker. McGill University, Montreal from September 2002 to April 2006. Subjects included University of Toronto varsity athletes participating in sports deemed high risk for concussion. Full The failure of damaged adult central nervous system neurons to informed consent was obtained from 318 athletes with no concussion in the regenerate can have devastating consequences, often resulting in permanent two years prior. Collected blood samples were genotyped and the presence of loss of sensory and motor function. Growth inhibitors present in myelin have APOEe4 was described dichotomously. There was no loss to follow-up. been identified as one of the major factors preventing CNS axonal Time to concussion was measured in two ways: athletic-exposures (number

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of games and practices); and number of games played. Only the first believed to play a prominent role, such as Parkinson’s disease (PD). Infusion concussion sustained by an individual was included in the analysis. Sport- of the bacterial endotoxin, lipopolysaccharide (LPS), into the substantia nigra medicine professionals who were present on the sidelines identified the pars compacta (SNc) has been reported to provoke many histological signs concussions. To assess misclassification, athletes self-reported if they of PD, including a loss of dopamine neurons and activation of microglia. incurred a concussion that was missed by the sport-medicine professional. Several pro-inflammatory cytokines, including interleukin-1beta (IL-1beta), The unadjusted hazard for concussion was 18% greater in individuals with IL-6 and tumor necrosis factor-alpha (TNF-alpha) modulate the central the APOEe4 allele than in those without (Hazard ratio (HR): 1.18 (95% effects of LPS. Accordingly, the present study evaluated the temporal confidence interval (CI): 0.52, 2.69)). Adjustment for sex, weight, height, sequence of PD-like behaviors and glial activation, as well as changes in a and team type resulted in a HR of 1.06 (95% CI: 0.41, 2.72). The estimates panel of 10 pro- and anti-inflammatory cytokines within the SNc, striatum including self-reported concussions were 0.96 (95% CI: 0.50, 1.85) for the and circulation following LPS infusion into the SNc. Indeed, intra-SNc unadjusted HR and 0.81 (95% CI:0.38, 1.73) for the adjusted HR. Similar endotoxin administration reduced home-cage activity 90 min and 2 days after results were obtained for the number of games played measure. treatment, suggesting that transient motor impairment was provoked by Our data indicate no statistically significant evidence for an association nigral inflammation. Although microglial activation was evident at 2 and 7 between the possession of an APOEe4 allele and concussion. Additional days after LPS, astrocyte immunoreactivity was unaffected. Time- and dose- study is required before we can be certain there is no relationship between dependent cytokine changes occurred following LPS, with levels of IL-6 and possession of APOEe4 and risk of concussion. TNF-alpha, together with the anti- inflammatory cytokine, IL-10 being increased within circulation and the SNc at the early 90 min interval. In contrast, circulating levels of IL-1beta, IL-2 and interferon-gamma (IFN- 374 A404 gamma) were elevated at the 7 day interval but only IL-1beta was increased INTRACEREBRAL HEMORRHAGE MODELS IN RAT: within the SNc following LPS. Within the striatum, LPS induced elevations COMPARING COLLAGENASE TO BLOOD INFUSION of IL-1beta and IL-6, which were sometimes relatively protracted. These data C.L. MacLellan1, G. Silasi1, C. Poon1, C. Edmundson2, R. Buist2, J. reinforce the notion that complex cytokine interactions and glial changes Peeling2, and F. Colbourne1. 1. Department of Psychology and Centre for may be important for the behavioral pathology observed in PD. Neuroscience, University of Alberta, Edmonton 2. Department of Pharmacology, University of Manitoba 376 A406 The autologous whole blood and bacterial collagenase models of A POSSIBLE NEUROPROTECTIVE ROLE OF NICOTINE intracerebral hemorrhage (ICH) are routinely used to study the pathology of THROUGH INDUCTION OF BRAIN CYP2D6 ICH and putative treatments. By directly comparing models, we aim to Mann, Amandeep, M.Sc., Miksys, L. Sharon, Ph.D., Tyndale, F. Rachel, highlight differences between the models and limitations of each in Ph.D. Centre for Addition and Mental Health and the Department of experimental ICH studies. Thus, we assessed the time course of bleeding and Pharmacology, University of Toronto tracked the progression of injury and behavioral deficits in the whole blood and collagenase ICH models. In Experiment 1, we assessed hematoma CYP2D6 is an enzyme which is expressed in liver and at lower levels in volume using a spectrophotometric hemoglobin assay at 1, 2, and 4 h after number of extra hepatic tissues including the brain. It is involved in the ICH (N = 60). Blood volume significantly increased from 1 to 4 h in the metabolism of numerous CNS drugs (e.g. antidepressants, neuroleptics), collagenase model, but not after blood injection. In Experiment 2 (N = 40), endogenous neural compounds (e.g. catecholamines) and the inactivation of we attempted to match the collagenase insult to the standard 100 ?L whole neurotoxins such as pesticides and 1-methyl 4-phenyl 1,2,3,6- blood model. Thus, we used 0.2 U of bacterial collagenase to produce similar tetrahydropyridine (MPTP). Association studies indicate that poor hematoma volumes. In Experiment 3, magnetic resonance imaging (MRI) metabolizers of CYP2D6 are over represented in Parkinson’s Disease (PD) was used to track the ICH over 6 weeks (N = 40). T2 weighted images were and show an even greater risk when exposed to pesticides. Conversely obtained at 6 h, 12 h, 2 d, 4 d, 1 wk, 2 wk, 4 wk, and 6 wk following ICH. smokers display a 50% reduction in risk for developing PD; smokers also We also assessed neurological deficits 1 - 28 days after ICH. Damage to the have higher levels of brain CYP2D6. Therefore, one possible mechanism of striatum and to distal regions including the cortex, substantia nigra, and white neuroprotection against PD by smoking may be through induction of the matter tracts was measured at 6 weeks. Hemoglobin breakdown occurred neurotoxin-inactivating enzyme CYP2D6 in the brain. To test if nicotine, faster after blood injection than after collagenase-induced ICH. Analysis of found in cigarette smoke, induces CYP2D6 in the brain, non-human primates MR images revealed that early hematoma volume (e.g., 6 h after ICH) were chronically treated with nicotine (0.3 mg/kg b.i.d., s.c., 18 days) and significantly correlated with eventual tissue loss (at 6 wk) in the blood immunoblotted for brain CYP2D. In these monkeys we identified three infusion model, but not in the collagenase model. Neurological deficits different CYP2D6 like proteins in the brain with molecular weights of 55, 52, completely recovered by 3 weeks in the whole blood model, whereas and 49 kDa. The major CYP2D forms (55 & 52 kDa) showed an induction recovery in the collagenase rats was more gradual. Long-term histological upon treatment with nicotine in various regions including those affected in injury included damage to the striatum and distal regions, and was much PD such as substantia nigra (2.4-fold, p=0.016), putamen (3-fold, p=0.01), greater in the collagenase model, despite a slightly smaller initial hematoma caudate (2-fold, p=0.03) and brainstem (2-fold, p=0.001). Preabsorption with volume. Subtle functional deficits and limited injury after blood infusion the human CYP2D6 peptide confirmed that the antibody is specifically make this model less suitable for long-term studies testing therapeutics. binding to CYP2D6-like proteins. In addition, antibody purification using monkey liver CYP2D indicates that all three bands show homology to the single form of CYP2D detected in monkey liver. Comigration and spiking 375 A405 studies suggest that the 49 kDa protein has the most similarity to the monkey TEMPORAL PATTERNS OF PERIPHERAL AND CENTRAL liver CYP2D. The two major brain CYP2D forms (55 & 52 kDa) may be CYTOKINE EXPRESSION AND GLIAL REACTIVITY PROVOKED brain specific isoforms or post-translationally modified CYP2D proteins. In BY INFUSION OF LIPOPOLYSACCHARIDE INTO THE conclusion, these results suggest that monkey brain expresses three forms of SUBSTANTIA NIGRA PARS COMPACTA CYP2D and two are induced in a brain-region specific manner upon Emily Mangano* & Shawn Hayley. Institue of Neuroscience, Carleton treatment with chronic nicotine. Funded by: Tobacco Use in Special University, Ottawa Populations, CAMH, CIHR MOP14173, and CRC.

Neuroinflammatory processes have been implicated in several neurological conditions, including those in which environmental insults are

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377 A407 area and to the striatum. (Supported by an H.H. Jasper fellowship and CIHR GLOBAL ISCHAEMIA INDUCES ENHANCED BRAIN DAMAGE grant MOP-3544). DURING PREGNANCY: ASSESSMENT OF HIPPOCAMPAL INJURY AND MEMORY Sarah J. Spencer, Michael A. Galic, Quentin J. Pittman and Abdeslam 379 A409 Mouihate*. Hotchkiss Brain Institute, Department of Physiology and CLUSTERED OBSTRUCTIVE APNEAS INDUCE LONG-TERM Biophysics, Faculty of Medicine, University of Calgary FACILATATION OF UPPER AIRWAY MOTOR OUTFLOW IN SPONTANEOUSLY BREATHING RATS IN-VIVO The female rat undergoes myriad physiological, endocrine and Tadjalli A*., Duffin J. and Peever J.H. Departments of Cell & Systems neurological alterations during pregnancy. Some of these changes are known Biology and Physiology, University of Toronto to have differential effects on the susceptibility to, or outcome following, a cerebrovascular event. Clinical evidence indicates that females are at greater Objectives: Respiratory long-term facilitation (LTF) is a long-lasting risk for thromboembolic stroke and ischemic injury during pregnancy. increase in respiratory motor outflow that is induced by episodic but not Although the increased risk has been linked to hormonal surges that continuous hypoxia. While three 5-minute periods of hypoxia have been encourage a pro-coagulant cardiovascular state, the precise mechanisms have shown to induce LTF, it is unknown if brief periods of asphyxia produced by not been resolved. In order to further explore the nature of the association apneas that are physiologically relevant (as in obstructive sleep apnea) also between stroke and pregnancy, we used the two vessel occlusion (2VO) induce LTF. Therefore, the aim was to determine whether clustered method to induce a brief (15 min) period of global ischemia in either (repeated) airway occlusions evoke respiratory LTF. Methods: Experiments pregnant (day 17) or virgin Sprague-Dawley rats. Three days following 2VO, were performed on anesthetized (2% Isoflurane in 50% O2 / 50% N2), rats were assessed in the open field for anxiety and locomotor behaviours, or tracheostomized, spontaneously breathing adult male Sprague-Dawley rats for learning and memory in a contextual fear conditioning paradigm. (n=17; 300-380g). Respiratory motor activity was determined by recording Following the behavioural examinations, rats were sacrificed for histological the EMG activity of both diaphragm and genioglossus muscles. Airway inspection of the hippocampus. Preliminary results revealed that pregnant occlusions (apneas) were induced by obstructing tracheal airflow using a rats exhibited increased behavioural deficits in the conditioned fear test and specially-constructed device. Following a 30-45 minute stabilization period, enhanced neuronal injury subsequent to 2VO compared to virgin females. one of 2 experimental protocols was executed. Protocol 1, rats (n=8) were Thus our initial experimental findings support the clinical association not exposed to apneas, and respiratory motor activity was recorded for 120 between stroke-induced damage and pregnancy. This stroke model is minutes. This group served as a control. Protocol 2, respiratory motor currently used to uncover the mechanisms of stroke-induced enhanced brain outflow was recorded for 60 minutes before and after exposure to a cluster of damage during pregnancy. ten 15-second airway obstructions, each separated by 1 minute (n=9). This protocol was hypothesized to evoke respiratory LTF. Results: Respiratory frequency and amplitude of both the diaphragm and genioglossus muscle 378 A408 activities remained unchanged throughout the 120-minute recording period DISTRIBUTION AND ULTRASTRUCTURAL FEATURES OF THE in the control experiments (1-way ANOVA, P>0.05). During each of the ACETYLCHOLINE INNERVATION IN ADULT RAT THALAMUS occlusions, the inspiratory amplitude of both diaphragm and genioglossus Martin Parent *, Laurent Descarries. Departments of Pathology and Cell muscles increased. After the ten airway occlusions, the amplitude of the Biology and of Physiology, GRSNC, Faculty of Medicine, Université de genioglossus inspiratory motor outflow transiently returned toward baseline Montréal, Montreal levels and then over the subsequent 60 minutes, increased to levels significantly greater than baseline (168 ± 12%; 1-way ANOVA, P<0.05). The rodent thalamic nuclei share an heterogeneous acetylcholine (ACh) Respiratory frequency, and the amplitude of diaphragm inspiratory activity innervation arising essentially from the brainstem cell groups Ch5 and Ch6 remained stable and were unchanged during the post-apneic period (1-way (pedunculopontine and laterodorsal tegmental nucleus). We used a highly ANOVA, P>0.05; fig. 1). Conclusions: These observations demonstrate that sensitive monoclonal antibody against rat choline acetyltransferase (ChAT) repeated airway obstructions evoke LTF in genioglossus motor activity. (Cozzari et al., 1990) to quantify this innervation and determine its Accordingly, we suggest that respiratory LTF of upper airway muscles may ultrastructural characteristics in three functionally distinct thalamic nuclei: be a protective mechanism for maintaining airway patency, which may play the parafascicular nucleus (PF), reticular thalamic nucleus (Rt) and dorsal a role in obstructive sleep apnea. lateral geniculate body (DLG) of adult rat. At the light microscopic level, the density of ACh innervation was quantified by unbiased, stereological counts of ChAT+ axon varicosities (terminals) with the optical fractionator (Stereo 380 A410 Investigator, MicroBrightField). It was the highest in PF (2.1 millions CEREBELLAR NUCLEI OF THE GOAT(CAPRA HIRCUS) varicosities/cu. mm), followed by Rt (1.7 millions) and DLG (1.3 millions). Asmaa Tajjiou, Ouassat Mohamed Based on cell counts in adjacent Nissl-stained sections, the corresponding numbers of ACh axon varicosities per thalamic neuron were 43 in PF, 57 in This study, aimed to investigate the microscopic anatomy and topography Rt and 33 in DLG. At the ultrastructural level, ACh axon varicosities in the of the goat (capra hircus) cerebellar nuclei, was carried out on eight three nuclei were comparable in shape, vesicular content and frequency of cerebellums of local breed of goats aged less than two years. These mitochondria, but were significantly larger in PF than in Rt and DLG. In cerebellums were subjected to a histological study through various plans of single thin sections, the proportion of ChAT+ varicosity profiles displaying a anatomical cuts (sagittal, transversal and frontal), using haematoxylin- eosin symmetrical or asymmetrical synaptic contact was 25% in PF, compared to and toluidine blue stains. The comparative anatomy of the goat cerebellums only 10% in Rt and 8% in DLG. When extrapolated to the whole volume of enabled us to detect the analogies and differences with the other species of varicosities, these values indicated that the ACh innervation of PF is entirely mammals including the weight, dimensions and the morphology. The synaptic (109%), at variance with Rt and DLG, in which only 39% and 33% histological study of the cartography of the cerebellar nuclei highlighted the of the ACh varicosities are synaptic. Thus, in Rt and DLG, modulatory similarities as well as the specific characteristics concerning the situation, the effects of the ACh input from brainstem are presumably conveyed by diffuse shape, the delimitation, the cytology of these cerebellar nuclei. The cerebellar transmission and spread onto a large number of units within the nucleus. In nuclei of the goat form a nuclear mass of 0.9 cm length, 1.3 cm width and 0.7 contrast, in PF, the entirely synaptic ACh input would allow for a more cm height. As a whole, the goat cerebellar nuclei is closer to that of the sheep faithful relaying of this excitatory drive from brainstem to extensive cortical and the bovine on the frontal cuts, with some similarities with camelids, equids and rodents on the other cuts.

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381 A411 were rewarded for fixating a central point while a series of 7 successive EFFERENTS OF AMYGDALA TO HIPPOCAMPUS IN PROTEIN stimuli were briefly flashed (100 ms duration; 100-400 ms interval) in the DEFICIENCY receptive field of the neuron. On 70% of trials all flashed stimuli were Hassanzadeh,Gholamreza-Barzrodipour,Mitra-Bayat,Mohammad. identical, while on others, the 4th was either brighter, dimmer or absent (10% Department of Anatomy-School of Medicine-Medical sciences/Tehran each). If reduced neural response is due to habituation, some recovery of the University response (dishabituation) should occur to any oddball stimulus. However, if the reduced response is due to adaptation, the response should be further Amygdala and Hippocampus are important parts of the brain and proteins reduced after the brighter, but recover after the dimmer or absent stimulus. are essential cellular elements in all live beings.Protin deficiency is one of the The largest decrease in response (often > than 50%) was to the second commonest kinds of malnutrition in the world.Therefore we investigated the stimulus, and subsequent stimuli resulted in only small further reductions. effect of low protein diet on efferents of amygdala to CA1 of hippocampus. The shorter the inter-flash interval, the greater these reductions. The pattern In this study,26 Rats randomly divided into two groups(case & was globally similar in SCs and SCi, but there was a greater reduction to the control).During 7 months control group was fed with normal diet(18% 3-7th stimuli in SCi. Responses to oddball stimuli in SCs neurons were protein)and case group was fed with low protein diet(8% protein).After 7 suggestive of adaptation, while responses in SCi neurons showed features of months HRP injected into CA1 of hippocampus in two groups.After 48 to 72 both adaptation and habituation. hours of survival time each animal was deeply anesthetized and perfuzed transcardialy with fixative solution.The brains were removed from skull postfixed. sections were cut at 40 micro meter by using cryostat microtom 383 A132 along the frontal plane. For the histochemical demonstration of HRB, serial ACTIVATION OF PPTg NEURONS INHIBITS AUDITORY sections were treated with TMB reaction. The sections were mounted on EVOKED EPSCs IN STARTLE MEDIATING NEURONS BY A gelatin - coated slides and constrained with neutral red. Topographical study MUSCARINIC MECHANISM of labeled neuronal cell was performed by light microscope. Selected Daniel Bosch1, John S. Yeomans2, Susanne Schmid1,2. 1 Tierphysiologie, sections were drowing by microprojector. We used image TOOL 2 and SPSS Zool. Inst., Universität Tübingen, Deutschland 2 Department of Psychology, 11.0 (T test & mannwithney ) software for analysis of results. Findings: University of Toronto following injection HRP to CA1 region of hippocampus in the control group rats. labeled neurons were more density in the centrolateral regions of BLP, Giant neurons in the caudal pontine reticular formation (PnC) are the BMP,LaVM, Aco, PMCo, MePD and MePV nuclei of amygdala that these central structure of the mammalian startle response. They receive input from neurons decrease toward rostral and caudal ends of these nuclei.Also these sensory nuclei and directly project onto motoneurons. Furthermore they neurons were more density in the posterolateral region of integrate different modulatory inputs either enhancing or inhibiting startle BLA,BLV,BMA,LaVL,PLco and MeAD nuclei.Labeled neurons were more response. One important modulation is prepulse inhibition (PPI) of the startle density in the anterolateral of the LaDL nuclei of amygdala that decreased by a preceeding nonstartling stimulus. PPI reflects a sensory filtering toward caudal ends of its nucleus. Conclusions:Our finding show that mechanism and is impaired in many neurological disorders. Different different nucleus of amygdala send projections to CA1 region of behavioural studies indicated that PPI of the startle response is mediated by hippocampus. Among of these nuclei,basolateral nuclei group sends the most an cholinergic projection from the pedunculopontine tegmental nucleus projections. In comparison of the case and control groups we found that (PPTg) onto PnC neurons activating muscarinic receptors. effect of low protein diet on efferent from basolateral, cortical and medial Electrophysiological studies confirmed a strong inhibition of trigeminal and nucleus of amygdala to the CA1 region of hippocampus are decreased. auditory evoked currents in PnC giant neurons by the application of muscarinic agonists. We here combined presynaptic extracellular stimulation of auditory fibres and descending fibres from PPTg to PnC in rat slices in order to show that the activation of PPTg neurons indeed inhibits sensory inputs to the PnC at different interstimulus intervals (ISI). Furthermore, we SENSORY & MOTOR SYSTEMS applied the cholinergic blockers mecamylamine and scopolamine in order to determine the involved receptors. Burst stimulation of PPTg fibers prior to auditory fiber stimulation significantly inhibited auditory evoked EPSCs at 382 A131 ISIs of 300 and 1000ms (83.6 ± 6.3%, n=11 and 81.9 ± 4.5%, n=11 of control ADAPTATION AND HABITUATION OF VISUAL RESPONSES IN amplitude, respectively). In addition, paired-pulse ratio was significantly THE SUPERFICIAL AND INTERMEDIATE LAYERS OF THE increased at an ISI of 1000ms. The application of mecamylamine, a nicotinic SUPERIOR COLLICULUS (sc) antagonist, had no significant effect on burst induced inhibition at ISIs of 300 *Susan Boehnke 1, David Berg 2, Pierre Baldi 3, Laurent Itti 2, Doug Munoz and 1000ms. In contrast, the muscarinic antagonist scopolamine significantly 1. 1 Centre for Neuroscience Studies & Department of Physiology, Queen's blocked PPTg induced inhibition in the PnC as well as the changes in paired- University, 2 Department of Computer Science, University of Southern pulse ratio at 1000ms ISI (p=0.036 and p=0.029, n=4). We therefore California 3 Department of Computer Science, University of California conclude that PPTg activation inhibits sensory signals in PnC giant neurons Irvine at ISI of 1000 ms in vitro by the activation of presumably presynaptic muscarinic receptors. One neural correlate of visual attention is a decrease in the neural response to a target after prior presentation of an orienting 'cue' (e.g. inhibition of return). This decreased responding could be the result of 384 A133 repeated stimulation of a neuron's receptive field resulting in either RESPONSES IN THE PRIMARY AUDITORY CORTEX IN 'adaptation' – a lower level mechanism related to neural fatigue, or TINNITUS SUFFERERS AFTER INDUCTION OF RESIDUAL 'habituation' – where an organism stops responding to an irrelevant stimulus INHIBITION BY MASKING SOUNDS but recovers the response after a change in stimulus properties. We Bosnyak D.J., Leone A.M., Gander P.E., Roberts L.E. McMaster University dissociated adaptation from habituation in superficial (SCs) and intermediate (SCi) layer neurons of the SC, a hub of oculomotor and attentional Tinnitus, a phantom auditory sensation in the absence of external stimuli, processing. SCs receives visual input from the retina directly or via V1, while may be briefly suppressed after the cessation of a masking sound. This is the SCi receives convergent input from visual and motor areas. Monkeys called residual inhibition (RI) in the tinnitus literature. Typical tinnitus

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sufferers experience 20-30 seconds of RI although some subjects experience 386 A135 no RI. In this study tinnitus sufferers who have previously demonstrated RI PERCEIVED PAIN INTENSITY MODULATES BRAIN RESPONSES were compared to normal hearing controls without tinnitus. In our model, TO FACIAL EXPRESSIONS TO PAIN tinnitus sensations are generated by abnormal synchronous neural activity L. C. Budell (1), P.L. Jackson (2), P. Rainville (3). (1) Physiologie, that develops in the primary auditory cortex (PAC) and other auditory regions Université de Montréal, Montréal (2) École de Psychologie, Université consequent on weakened intracortical inhibition associated with hearing loss Laval, Québec (3) Stomatologie, Université de Montréal, Montréal or the aging process. Neural responses in the PAC can be measured using 40 Hz amplitude-modulated (AM) probe tones which produce a 40-Hz auditory Results of brain imaging studies on pain empathy suggest that the neural steady-state response (ASSR) in the EEG. substrate of the perception of pain in others includes cortical areas involved Tinnitus subjects and normal hearing controls underwent two conditions in the affective dimension of the perception of pain in the self. In this case, in which ASSR amplitude was expected to differ. One condition consisted of it is likely that at least some brain areas responsive to the perception of pain only probe tones (TINN condition) while the second condition included expression should code for the intensity of the pain expressed. This study probe tones which followed maskers designed to elicit RI in the tinnitus investigated the differential engagement of emotional, sensory and motor group (RI condition). It was hypothesized that there will be an increase in brain areas in observers evaluating dynamic facial expressions of pain, and ASSR amplitude in tinnitus subjects during the RI condition compared to the how activation in these areas is modulated by intensity of the pain as TINN condition, as neurons temporarily desynchronized by the masker are perceived by the subject. BOLD-signal changes were measured in a 3T fMRI available for entrainment by the AM envelope. Analysis showed that ASSR scanner using an event-related design in 18 normal volunteers. Subjects amplitude increased in the tinnitus group after the masker (RI condition) viewed a series of 1-sec video clips displaying facial expressions of pain of compared to the TINN condition but decreased in the control group. This varying intensity. In each trial, subjects were cued to perform either a pain interaction was significant at p=.026. In addition, there was a main effect of evaluation task or a movement discrimination task. After each stimulus, group (tinnitus versus control) showing aSSR amplitude to be larger overall subjects rated the intensity of the pain expressed (pain task) or the relative in tinnitus (p = 0.01). These results are consistent with the view that magnitude of movements in the lower versus upper face (control movement hypersynchrony in auditory regions of the brain generates tinnitus, and that discrimination task). Brain response to pain was first examined by desyncronization by masking sounds underlies RI. Supported by CIHR, contrasting activation in response to pain versus neutral expressions in both NSERC, and the American Tinnitus Association. task conditions. Pain-related activity was observed in both emotional- and motor-related areas including medial prefrontal cortex (mPFC), cingulate cortex (CC), insula, pre- and primary motor areas; and secondary sensory 385 A134 areas (t > 4; p < .001). A contrast of the pain-related activation in the two task ONTOGENETIC DEVELOPMENT OF ACOUSTIC FEATURES OF conditions was then done in order to identify areas of activation associated ISOLATION CALLS IN WISTAR RATS with attention to, and evaluation of, the pain expressed. Activation during the Lindsay E.C. Shields*, and Stefan M.Brudzynski. Department of Psychology pain evaluation task was significantly stronger in medial PFC areas including and Centre for Neuroscience, Brock University, St. Catharines perigenual and dorsal ACC. We then examined the relationship between the magnitude of brain response and the intensity of the pain as perceived by the Rat pups are known to emit an acoustically heterogeneous group of observer. A modulatory effect was found in medial PFC as well as in bilateral ultrasonic isolation calls, while adult rats develop two distinct ultrasonic insula, suggesting that assessment of the amount of pain expressed by vocalization types with the respective peak frequencies of 22 kHz and 50 another involves emotional and social cognition systems in the observer. kHz. The goal of the present study was to analyze acoustic features of isolation calls emitted by individually studied Wistar pups from 3 to 20 days of age and observe a postulated transition from the infantile to adult type of 387 A136 ultrasonic calls. Pup vocalizations were induced by a mild and unpredictable GLUTAMATERGIC CONTROL OF SOMATIC MOTONEURONS IN air puff delivered from above the animal. Most animals emitted calls, FREELY-BEHAVING RATS particularly at younger ages. Overall, the duration of individual calls *C Burgess1,D Lai2, J Siegel2 and J Peever1. 1Departments of Physiology increased with age, while the individual call frequency showed a decreasing & Cell and Systems Biology, University of Toronto; 2Department of tendency. The isolation calls were divided into those with short call duration Biobehavioral Sciences, UCLA, Los Angeles, USA (less than 100 ms) and those with long call duration (longer than 100 ms), as well as into those with high peak frequency (higher than 50 kHz) and low Skeletal muscle activity is potently suppressed in sleep and particularly peak frequency (lower than 50 kHz). Calls longer than 100 ms showed a during REM sleep. Abnormalities in muscle tone underlie most of the major significant negative correlation with age for sound frequency (r = -0.88, p< sleep disorders including narcolepsy, REM-sleep behaviour disorder and 0.0001) and positive correlation with call duration (r = 0.65, p< 0.003). Thus obstructive sleep apnea. The biochemical mechanisms that mediate in this category, the call duration lengthened and frequnecy decreased with suppression of muscle tone in sleep are unclear. In the current study, we increasing age of the pup. These calls had also increasingly flat sonographic hypothesize that withdrawal of excitatory glutamatergic inputs onto somatic appearance (decrease in their bandwidth, p < 003) and their number increased motoneurons may be responsible for sleep-dependent reductions of muscle with age (p < 001). Calls with duration under 100 ms decreased with age (p tone. To test this hypothesis, we exogenously applied (using microdialysis < 0006), but did not show any significant change in peak frequency or call probes) either glutamatergic agonists (glutamate, NMDA and AMPA) or duration. These changes were consistent with those observed for calls under antagonists (CNQX and D-AP5) onto trigeminal motoneurons in freely 50 kHz. Their frequency decreased (r = -084, p < 0.0001) and call duration behaving rats (n=24) while recording masseter EMG activity across the increased with age (r = 0.7, p < 0.001). Calls with a peak frequency higher natural sleep-wake cycle. Glutamate receptor antagonism led to significant than 50 kHz did not show significant changes in duration, however their peak decreases in masseter activity in waking (p=0.001), but had no effect during frequency significantly increased with age (r = 0.8, p< 0.0003). Overall, the either NREM (p=0.879) or tonic REM sleep (p=0.939). However, we found results indicate that the call pattern, which is compatible with the adult 22 that blockade of non-NMDA receptors abolished phasic muscle activity kHz alarm calls gradually develops and emerges early in infancy. during REM periods. While application of glutamatergic agonists Study supported by NSERC of Canada significantly increased masseter activity during both waking (p=0.001) and NREM (p=0.002), they had no effect on EMG activity in tonic REM sleep (p=0.916); however, glutamatergic agonists significantly enhanced muscle activity during phasic REM periods. We conclude that: 1) glutamatergic

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inputs play a predominate role in motoneuron excitation during wakefulness the objects were placed beyond the target strip, suggesting the obstacle but play a minor role during NREM and tonic REM sleep; 2) since avoidance system is sensitive to the depth at which an object becomes an exogenous application of glutamate onto motoneurons is unable to overcome obstacle. In a second experiment, we varied the height of the two objects, as the atonia of REM sleep, other powerful inhibitory mechanisms must be well as the depth. Object pairs could now be both tall, both short, or one involved; and, 3) phasic REM events are mediated by glutamate acting short and one tall (with the tall on the right or on the left). We replicated the primarily on non-NMDA receptors. first experiment, extending the finding to include sensitivity to the size of the objects. Here the deviations induced by short objects, while still significant, were significantly less than the tall-object deviations. Taken together, these 388 A137 experiments indicate a sophisticated obstacle avoidance system that is SEPARATE EXTRASTRIATE VISUAL REGIONS PROCESS FORM extremely sensitive and conservative in evaluating potential obstacles and AND TEXTURE IN THE ABSENCE OF EXPLICIT DEPLOYMENTS deviating reach accordingly. OF ATTENTION Jonathan S. Cant abc, Stephen R. Arnott ac, & Melvyn A. Goodale abc. a CIHR Group on Action and Perception b Neuroscience Graduate Program, 390 A139 University of Western Ontario c Psychology Department, University of HEAD-FREE ELECTRICAL STIMULATION OF THE LATERAL Western Ontario INTRAPARIETAL AREA (LIP) AND THE SUPERIOR COLLICULUS (SC) OF THE MACAQUE MONKEY We recently demonstrated that attending to either the form or surface A.G. Constantin 1,3, E.M. Klier 5, H.Wang 3, J.C. Martinez 4 and properties of objects activates anatomically distinct regions of occipito- J.D.Crawford 2,3. 1 York University, Biology dept., 2 York University, temporal cortex (Cant & Goodale, 2007). Specifically, attending to form Biology, Psychology, Kinesiology and Health Sciences, 3 Center for Vision activated the lateral occipital area (LO), whereas attending to texture Research, 4 McGill University, Psychology dept., 1,2,3 Center for Vision activated the collateral sulcus (CoS). Although these regions showed Research - York University, 5 Anatomy and Neurobiology dept., Washington preferential activation to one particular stimulus dimension (e.g. texture in University CoS), they also showed activation to other, non-preferred stimulus dimensions (e.g. form in Cos). Thus, one might question whether the Previous neurophysiological studies on head-unrestrained monkeys activation to form in CoS, for example, represented form processing, or established that coordinated eye and head movements (gaze shifts) are represented activation to changes in texture while people attended form. To evoked by stimulating the superior colliculus (SC - Klier et al. 2001). The investigate this, we conducted an fMR-adaptation experiment which allowed evoked gaze shifts are encoded in an eye-fixed frame. However stimulation us to examine the response properties of regions specialized for processing of LIP in head-restrained and head-partially-restrained monkeys evokes form, texture, and colour when participants were not explicitly attending to a saccadic eye movements (Thier & Anderson, 1996, 1998). It is not known particular stimulus dimension. Participants passively viewed blocks where whether LIP stimulation evokes coordinated eye and head movements (gaze only one dimension varied and blocks where no dimensions varied, while shifts) in head-unrestrained monkeys and what is the frame of reference used fixating a cross in the centre of the display. Area LO was most sensitive to by LIP to encode gaze. The goal of the present study was to examine if LIP variations in form, whereas CoS was most sensitive to variations in texture. and SC play a comparable role in gaze motor control. To test this we As in our previous study, no regions were found that were most sensitive to implanted recording chambers over the stereotaxic coordinates of the LIP and variations in colour. Taken together, these results replicate the findings from SC (two monkeys each) and eye search coils for 3-D recordings. The animal our previous study but also suggest that area LO and CoS can respond in a was trained to fixate targets while we electrically stimulated the SC (with very stimulus-driven manner in the absence of explicit deployments of stimulation trains of 20-50 µA and 200 ms) and the LIP (with stimulation attention. Furthermore, these results provide additional evidence for the trains of 150-200 µA and 200 ms). The head was unrestrained during training existence of separate processing pathways for form and texture in occipito- and stimulation. Stimulating SC we evoked contralateral gaze shifts with temporal cortex. amplitude varying from 4.52° to 90.43°, with a large range of eye and head as oppose to stimulating LIP which evoked smaller amplitude gaze shifts, varying from 2.45° to 18.2°, with a less than 1° head movement component 389 A138 (in the majority of sites). Using gaze shifts evoked from a variety of initial OBSTACLE AVOIDANCE WHILE REACHING: EFFECTS OF eye and head positions, and a method described by Klier et al (2001) we OBSTACLES AND NON-OBSTACLE OBJECTS ON REACH examined the reference frame used by the two brain areas. The results TRAJECTORY suggest that both structures use an eye-fixed frame to encode gaze. The study Craig S Chapman, Melvyn A Goodale. University of Western Ontario suggests that although LIP stimulation produces small-medium saccades and SC produces a large range of eye-head gaze shifts, they form a continuum When reaching to objects, our hand and arm rarely collide with non- along an eye-fixed curve, in terms of their reference frame coding. target objects, even if our workspace is cluttered. The simplicity of these actions hides what must be a relatively sophisticated obstacle avoidance system. Recent studies on patients with optic ataxia and visual form agnosia 391 A140 have demonstrated that obstacle avoidance is an automatic process, likely EJACULATION-INDUCED ACTIVATION OF NMDA RECEPTORS governed by the dorsal stream (Schindler et al., 2004, Nature Neuroscience, AND MAP KINASE IN SPINOTHALAMIC CELLS IN THE 7(7):779-784, Rice et al., 2006, Experimental Brain Research, 174(1):176- LUMBAR SPINAL CORD OF MALE RATS 188). The current study sought to quantify how normal participants react to Cleusa V. R. de Oliveira* and Lique M. Coolen. Departments of Physiology changes in the size and position of non-target objects in and around their & Pharmacology and Anatomy & Cell Biology, The University of Western workspace. In the first experiment, 13 right-handed subjects performed Ontario, London reaches to a target strip in the presence of two non-target objects, which varied in depth and horizontal configuration. We found that objects with Previously we identified a population of lumbar spinothalamic (LSt) cells horizontal alignments that were asymmetric about midline created systematic that play a pivotal role in the control of ejaculation and comprise an essential deviations in reach trajectory away from midline, with participants seeming part of the spinal ejaculation generator in the male rats. Lesions of the LSt to maximize the distance away from the two objects. These deviations were cell population completely eliminate expression of ejaculation, while other significantly greater for objects nearer in depth and nearly disappeared when elements of male sexual behavior remain intact. Furthermore, LSt cells

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express Fos, a marker for neural activation, only with ejaculation, but not rats. In conclusion, intrathecal administration of NTS1 agonists decreases during other elements of sexual behavior. Currently, it is unknown which pain behavior in neuropathic animals for four consecutive weeks. Thus, these signal transduction pathways or neurotransmitters are involved in the results demonstrate that NT analogs may be an interesting way for the activation of LSt cells. Therefore, the goal of the present study was to therapy of painful neuropathies without having the unfavourable side effects investigate expression and activation of glutamate receptors as well as of opioids. (Supported by CIHR, FRSQ, and NIMH). phosphorylation of the MAP kinase pathway in LSt cells. Male Sprague Dawley rats were perfused with 4% paraformaldehyde immediately (0 minutes) or 30 minutes after display of one ejaculation or after expression of 393 A142 8 intromissions without display of ejaculation. Control males were taken SENSORY PROTECTION OF RAT MUSCLE SPINDLES from their holding cages and perfused. Spinal cords were removed, FOLLOWING PERIPHERAL NERVE INJURY AND sectioned, and immunoprocessed for galanin as a marker for LSt cells and REINNERVATION NMDA receptor subunit 1 (NR1), galanin and phosphorylated NR1 (pNR1; Amal Elsohemy 1, Richard Butler 2, James Bain 3, and Margaret Fahnestock 30 minute groups), or galanin and phosphorylated ERK (pERK; 0 minute 1. 1Department of Psychiatry and Behavioural Neurosciences, 2Department groups), using dual immunofluorescence. Results showed that the majority of of Pathology and Molecular Medicine, 3Division of Plastic Surgery, the LSt cells contained NR1. Moreover, NR1 receptors were activated in Department of Surgery, McMaster University, Hamilton males that displayed ejaculation but not in males that expressed intromissions and mounts, but did not ejaculate, evidenced by a significant increase in the Skeletal muscle function and structural integrity are dependent upon percentage of LSt cells expressing pNR1 (68.3% following ejaculation vs intact innervation. Following peripheral injury resulting in muscle 36.3% in the control group and 41% after intromissions). The percentages of denervation, the outcome of nerve surgery is likely to be poor if reinnervation LSt cells that contained pERK were increased in males that displayed is delayed. Prolonged muscle denervation results in irreversible muscle fiber ejaculation (90.4% vs 6.5% in control males). However, ERK atrophy, connective tissue hyperplasia, and deterioration of the muscle phosphorylation was also induced in males that displayed intromissions and spindles, specialized sensory receptors necessary for proper skeletal muscle mounts, but no ejaculation (49.8%). Together these results indicate that the function. The protective effect of temporary sensory innervation on glutamate receptor NR1 is activated in LSt cells specifically with ejaculation denervated muscle, prior to motor nerve repair, has been shown in the rat. and may in turn mediate the expression of ejaculatory reflexes. Sensory protected muscles exhibit less fiber atrophy and connective tissue Phosphorylation of ERK is correlated with intromissions as well as hyperplasia while maintaining greater functional capacity than denervated ejaculations and it is not clear if this signal transduction pathway is therefore muscles. The purpose of this study was to determine whether temporary specifically involved with control of ejaculation. These experiments form a sensory innervation also protects muscle spindles from degeneration. The first step towards a better understanding of the spinal control of ejaculatory results document deterioration of muscle spindles in muscle denervated for reflexes. six months and demonstrate a significant preservation of spindle number and morphology in sensory protected muscle, adding to the known means by which sensory nerves exert protective effects on denervated muscle. This 392 A141 finding further promotes the use of sensory protection for improving the POTENT ANTINOCICEPTIVE EFFECTS OF NTS1 AGONISTS IN outcome after peripheral nerve injury. A MODEL OF NEUROPATHIC PAIN L. Doré-Savard*1, A. Guillemette1, M.A. Dansereau1, G. Roussy1, K. Belleville1, N. Beaudet1, E. Richelson2 and P. Sarret1. 1Dept. of Physiology 394 A143 and Biophysics, Faculty of Medicine, Univ. of Sherbrooke, Sherbrooke, PQ, THE EFFECT OF INC (INTERSTITIAL NUCLEUS OF CAJAL) Canada. 2Dept. of Psychiatry and Psychology, Mayo Clinic College of STIMULATION / INACTIVATION ON NECK MUSCLE Medicine, Jacksonville, FL, USA SYNERGIES Farshadmanesh, Farshad * (1), Chang, Pengfei (2), Yan, Xiaogang (1), The tridecapeptide neurotensin (NT) induces central and peripheral Wang, Hongying (1), Corneil, Brian, D. (3), Crawford, J., Douglas (1).. 1. effects through three receptor subtypes : NTS1, NTS2, and NTS3. Both Centre for Vision Research and Departments of Biology and Psychology, NTS1 and NTS2 receptors are involved in mediating the naloxone- York University, Toronto 2. Department of Neurosurgery, Beijing Sanbo- insensitive antinociceptive effects of NT in a variety of analgesic tests Fuxing Neurosurgery Hospital, The Brain Sciences Institute of Beijing. 3. including hotplate, tail-flick, and writhing tests. However, the role of these Departments of Physiology, Pharmacology and Psychology, University of receptors has never been documented in chronic pain models. The goal of Western Ontario, London this study was therefore to evaluate the analgesic effects of NTS1 specific agonists in a rat neuropathic pain model. Neuropathy was induced by sciatic Research has shown that the interstitial nucleus of Cajal (INC) acts as a nerve constriction (Bennett’s CCI model), and the development of neural integrator for torsional/vertical components of eye position/head mechanical allodynia and thermal hyperalgesia on the ipsi- and contra-lateral posture. Unilateral stimulation of the INC produces torsional eye and head hindpaws was examined 3, 7, 14, 21 and 28 days post-surgery. Paw movements to positions that are maintained until stimulation is removed. withdrawal latencies to heat stimulation or von Frey filament application Also, unilateral INC inactivation produces relatively coordinated position- were assessed, before and 20 min after NT, NT69L, PD149163 holding deficits in both the eye and head. However, the recruitment of neck administration, using the Plantar and the von Frey tests, respectively. Rats muscles during INC stimulation/inactivation is unclear. We investigate the exhibited heat hyperalgesia and tactile allodynia over a 28-day testing period. recruitment of 6 pairs of bilateral neck muscles in two head-unrestrained Mechanical and thermal sensitivity in sham-operated and saline-treated rats monkeys (Macaca mulatta) before, during stimulation, and 40 minutes after remained unchanged throughout the testing period. Intrathecal injection of inactivation of the INC. We identified INC sites by unit recording, and NT (1 and 6 µg/kg) dose-dependently attenuated the mechanical allodynia subsequently stimulated (50 microamp., 200 ms, 300 Hz) and inactivated (by and thermal hyperalgesia on days 7, 14, 21 and 28 post-surgery. injecting 0.3 microliter of 0.05% muscimol) each site. We recorded three- Administration of the NTS1 agonists PD149163 (30 and 90 µg/kg) and dimensional eye/head movements using search coils within magnetic fields. NT69L (5 and 25 µg/kg) also produced both anti-allodynic and anti- By surgically implanting bipolar hook electrodes we recorded EMG hyperalgesic effects in the CCI model of neuropathic pain. Importantly, (electromyographic) activity in these neck muscles (Bilaterally): occipital suppressive effects of NT, NT69L, and PD149163 on heat hyperalgesia and capitis inferior (OCI), rectus capitis posterior major (RCPmaj.), biventor mechanical allodynia were also observed on the contralateral paws of CCI cervicis (BC), complexus (COM), splenius capitis (SP) and

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sternocleidomastoid (SCM). Inactivation of the INC produced eye and head hand, constant spatial errors of final hand orientation were smaller when the position-holding deficits (drift): clockwise (CW) / counterclockwise (CCW) subjects simultaneously reached out and rotated their hand to align it with the after left/right INC inactivation. In addition, the range of eye and head target, than when they held their arm extended and passively matched the position tilted torsionally, similarly CW/CCW after left/right INC orientation of their hand with the target, even though the latter task is inactivation. Our preliminary analysis of the EMG data from one animal (5 biomechanically simpler. This difference may reflect the engagement of on- left INC sites, 6 right INC sites) revealed an overall reduction in EMG line control mechanisms during reaching movements. To investigate this activity of both ipsi- and contralateral neck muscles. Although the severity of hypothesis, subjects were instructed to first align their hand to the angle of this reduction was different for ipsi- versus contralateral muscles. INC the target, and then to reach out to the target without changing the hand stimulation, on the other hand, caused an increase in overall EMG activity of orientation. Subjects actively oriented their right hand then reached with the both ipsi- and contralateral muscles. The initial comparison between our right arm to insert a rectangular handle into a slot fixed in different stimulation and injection data did not suggest a simple ‘opposite’ pattern. orientations, with and without vision of their hand. Errors in hand orientation Further analysis of both stimulation/injection data of more INC sites should of subject were compared for the initial and the final orientations of the hand, provide a better perceptive of neck muscle synergies. before and after each reach. ANOVA analysis showed smaller errors at the end of the reach than at the beginning (p<.05). Although subjects were instructed not to change their hand orientation while reaching, hand 395 A144 orientation did change during reaching in a way that reduced the final NEURAL CORRELATES FOR PRO-SACCADES AND ANTI- constant spatial orientation error. The finding that the initial orientation error SACCADES IN SUBSTANTIA NIGRA PARS RETICULATA is reduced despite the instruction not to correct is further evidence that Joanna L Gore1,2 , Robert A Marino1 and Douglas P Munoz1,2. 1Centre automatic error-correction mechanisms are activated during voluntary for Neuroscience Studies, 2Department of Physiology, Queen’s University, reaching movements. Kingston

The substantia nigra pars reticulata (SNr) is hypothesized to mediate the 397 A146 initiation of saccades through GABAergic projections to the superior EFFECT OF ARM ORIENTATION ON MOTOR TASK LEARNING colliculus (SC). The goal of the present study was to determine if these AND GENERALIZATION inhibitory inputs are involved in providing the SC with increased inhibition A.M. Green 1*, J.-P. Labelle 1, R. Shadmehr 2, J.F. Kalaska 1. 1. Dépt. de when suppression of an automatic saccade is required. To test this hypothesis Physiologie, Univ. de Montréal, Montréal 2. Biomedical Eng., Johns we recorded from neurons in the SNr of two monkeys trained to perform a Hopkins Univ., Baltimore, MD, USA randomly interleaved pro/anti-saccade task. The color of the central Fixation Point instructed the monkeys to either generate a pro-saccade towards the Reaching studies suggest that humans learn novel task dynamics by stimulus or to suppress this automatic response and instead generate a adapting internal models that transform planned changes in limb state into volitional anti-saccade away from the stimulus. These tasks allowed us to motor commands. Learning one task interferes with the ability to learn determine if and how SNr activity changed with task instruction. We found another in a closely adjacent workspace location, consistent with broad that neurons in SNr that increase their activity for saccades (burst neurons; spatial generalization (e.g., up to 80 cm away). Nonetheless, two different n=20) had more pre-stimulus and more peri-saccade activity when the tasks can be simultaneously learned for relatively small spatial separations of monkey executed an anti-saccade and they had less activity when the 14-24 cm. To explain these observations, the internal model was proposed to monkey mistakenly made a pro-saccade on an anti-saccade trial. SNr neurons be comprised of basis elements that reflect a multiplicative interaction that have high levels of activity during fixation and decrease their activity for between signals coding movement direction/velocity and limb position saccades (pause neurons; n=18) did not display differences in pre-stimulus (Hwang et al., 2003). In the current study we investigated whether the activity between pro and anti-saccade trials, but had less peri-saccade activity coordinate system of this representation reflects the extrinsic coordinates of when the monkey executed a correct anti-saccade. These findings suggest the hand or the intrinsic coordinates of the joints/muscles. We compared that the SNr burst neurons may provide the SC with the extra inhibition learning in four groups of subjects that made reaching movements from three required to suppress the automatic pro-saccade on anti-saccade trials, while pseudorandomly chosen start positions, each associated with distinct task the SNr pause neurons may be involved in the generation of the volitional dynamics (left: CW curl-field A; center: null; right: CCW curl-field B). anti-saccade away from the stimulus. Groups C1 and C2 encountered fields A and B during movements along hand paths that were close in cartesian space (1 cm separation). C1 subjects made all movements with the arm in the horizontal plane, whereas C2 subjects 396 A145 encountered field A with the arm in the horizontal plane but field B with the CONTROL OF THE SPATIAL ORIENTATION OF THE HAND arm in the parasagittal plane. Thus, movements in these two groups were DURING REACHING MOVEMENTS IN HUMAN SUBJECTS close in cartesian but distant in proprioceptive space. Groups D1 and D2 Gosselin-Kessiby1*, J. Messier2, J.F. Kalaska1. 1. Physiologie, 2. performed movements that were distant in both cartesian (24 cm separation) Kinesiologie, Universite de Montreal, Montreal and proprioceptive space (D1: all horizontal plane; D2: two arm orientations). When initial limb state was similar in both cartesian and Control of the spatial orientation of the hand is an important component proprioceptive space (C1) subjects failed to learn the two tasks. In contrast, of many reaching movements. To investigate the contribution of vision and when limb state differed in proprioceptive space (C2, D1, D2) significant proprioception in perception and control of spatial orientation of the hand, learning took place. Learning failed to generalize across significantly right handed subjects were tested in perceptual and motor tasks. In the different initial joint angles as C2 subjects showed generalization between perceptual task, subjects were asked to passively align a rotatable rectangular field A and center but not between field B and center. The results demonstrate handle held in the right hand (match) to that of a second handle held in the that differences in limb joint angles/proprioceptive state are sufficient to left hand (reference) fixed in different orientations. In the motor task, support simultaneous learning of multiple task dynamics. This observation subjects actively reached and oriented the right hand to insert the match provides further confirmation that the internal model is composed of neural handle into a slot fixed in the same range of orientations. Orientations of the elements that encode limb state in intrinsic coordinates. match handle were captured by a motion analysis system (Optotrak). Supported by NIH and CIHR. ANOVA analysis shows a strong effect of task (p<.05) with smaller errors in the motor than in the perceptual task. We found that without vision of the

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398 A147 many of these neurons exhibited burst onsets within 50 ms of perturbation THE FEEDBACK PATHWAY OF THE ONLINE CORRECTION onset. Of these 43 neurons, 39 exhibited significant tonic responses MECHANISM INCLUDES COMPENSATION FOR LIMB (χ2 test, P < 0.001). Of particular interest, the preferred directions of DYNAMICS phasic and tonic responses were tightly correlated (Rayleigh test, mean Gritsenko*, V., Yakovenko, S., and Kalaska, J. F. Université de Montréal vector = 0.59, P < 0.001). The distribution of preferred directions in M1 was also highly similar to those of upper arm muscles which showed similar Reaching movements to visual targets have been shown to be under fast conservation of preferred directions between phasic and tonic responses. feedback control. This is evident from the ability to rapidly adjust ongoing These findings suggest an important link between the neural processing in movement to a change in the location of its goal, i.e. online correction. This M1 for on-line control in which short-latency bursts can be viewed as rapid study addresses the organization of a feedback controller underlying online motor responses. correction by comparing performance of a virtual model arm to human movements. Human experiments were conducted with eight subjects, who performed reaching movements toward visual targets. In half of the trials, the 400 A149 target abruptly changed location by different amounts (3.5 – 14 deg along 15 ADAPTIVE RESCALING EXTENDS THE DYNAMIC RANGE OF cm radius) during the ocular saccade. The virtual arm was a dynamic 2-link CENTRAL VESTIBULAR SIGNALS IN THE ALERT CAT model of a human arm with viscous joints built in MatLab software. A Heskin R 1, Tan YF 1, Farrow K 2, Broussard DM 1,2,3. 1 Dept. of closed-loop controller drove the model arm by combining the feed-forward Physiology, Univ. of Toronto, Toronto 2 Dept. of Neurology, University of torque command to the original target location with either a position error Toronto, Toronto 3 Toronto Western Research Institute, University Health between desired and delayed actual positions of the arm endpoint (Kinematic Network, Toronto Feedback or KFb) or with a corrective torque based on this position error (Dynamic Feedback or DFb). Furthermore, delay-compensated feedback Adaptive rescaling adjusts the sensitivities of sensory responses for controllers, which included a forward dynamic model to predict current hand efficient signal transmission under varying stimulus conditions. The position from the efference copy of the motor command, namely Kinematic possibility that rescaling could improve the performance of the vestibulo- and Dynamic Feed-forward controllers (KFf and DFf), were also tested. The ocular reflex (VOR) after sensory loss has not been investigated. We human results showed that the hand trajectories deviated from the control recorded from isolated vestibular neurons in alert cats that had recovered trajectory proportionally to the size of the target jump. Target jumps in from peripheral vestibular damage. Stimuli consisted of rotation at 1 Hz with different parts of the workspace resulted in different amplitudes of online peak velocities of 10-120 deg/s. The sensitivities and dynamic ranges of correction. This scaling of online correction for movements in different vestibular neurons were measured. Significant rescaling was seen both directions was simulated well only by the model driven by DFb and DFf ipsilateral and contralateral to the damaged side. When the peak velocity controllers, while the model driven by KFb and KFf controllers produced increased by a factor of 8, the average sensitivity to rotation of the sample of asymmetric trajectory adjustments due to the inability of these controllers to neurons decreased by roughly a factor of 2. The dynamic ranges of central compensate for limb dynamics. The trajectories produced by the DFf neurons and of the VOR appeared to increase at higher peak velocities. Our controller showed the closest fit to the human position and velocity results suggest that after vestibular damage, adaptive rescaling improves trajectories across a range of model parameters and this controller was found signal transmission by central vestibular neurons and may act to restore the to have the lowest parametric sensitivity. Furthermore, the DFf controller dynamic range in the response of the VOR to rotation at high speeds. was the only one to show best fits to human data within the range of physiological joint viscosities. These results support an online controller design that uses an error signal derived from the difference between the 401 A150 original motor program and feedback about the actual movement, and which BLOCKING THE GLUCOCORTICOID RECEPTOR emits a corrective motor command that takes into account limb dynamics. NEUTRALIZES MOTOR FUNCTION IMPAIRMENT ASSOCIATED WITH STRESS Nafisa M. Jadavji* and Gerlinde A. Metz. Canadian Centre for Behavioural 399 A148 Neuroscience, University of Lethbridge PRIMARY MOTOR CORTEX ACTIVITY EXHIBITS SIMILAR REPONSES TO TRANSIENT AND CONSTANT LOADS DURING Stress is one of the most critical influences on behaviour and POSTURE performance. While most research has focused on the effects of stress on T. M. Herter and S. H. Scott. Department of Anatomy and Cell Biology, limbic system functions, including learning and memory, recent findings Canadian Institute of Health Research Group in Sensory-Motor Systems, and have shown that stress is also a modulator of motor control. For instance, Centre for Neuroscience Studies, Queen's University, Kingston stress can impair skilled and non-skilled movements in intact rats. The mechanisms by which stress and stress hormones exert these effects, It is well known that primary motor cortex (M1) is an important neural however, have not been determined yet. Previous data suggest that the stress structure for performing volitional motor behaviours. A hallmark of M1 is hormone corticosterone mediates at least some of the effects of stress on the that the activity of individual neurons is commonly modulated by mechanical motor system. The purpose of this study was to investigate if the impact of loads applied during various motor tasks. It is less appreciated that M1 stress and corticosterone on motor function can be neutralized by a neurons exhibit relatively short-latency (<100 ms) phasic responses to glucocorticoid receptor (GR) antagonist. Groups of male and female rats mechanical perturbations. We have studied the relationship between phasic were tested in a skilled reaching task while receiving daily treatments of and tonic responses to torques imposed at the shoulder, elbow, or both joints either immobilization stress or oral corticosterone. On Day 1 and Day 13 of in monkeys during whole-limb postural maintenance. Phasic responses were treatment, rats were administered the glucocorticoid receptor antagonist RU- measured 25–100 ms after the onset of brief torque perturbations (300 ms) 486. While both acute and chronic stress and corticosterone treatments that were applied while the hand was stabilized at a spatial target. Tonic reduced skilled reaching success, administration of RU-486 neutralized these responses to constant torques were measured 1000–3000 ms after posture effects by protecting skilled reaching success. There was no difference was maintained at the same spatial target. The relationship between phasic between male and female rats in the reaction to any of the treatments. These and tonic responses was investigated by examining their directional tuning observations suggest that corticosterone plays a central role in modulating properties in joint-torque space (planar regression fits, P < 0.01). This motor system function, and that these actions are mediated through GR analysis revealed 43 neurons with significant phasic responses, of which activation. Supported by: Alberta Heritage Foundation for Medical Research and Canadian Institutes of Health Research.

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402 A151 with increasing elbow flexor motion. A second set of perturbations further PHASE AND TASK SPECIFIC MODULATION OF THE SOLEUS confirmed the influence of elbow motion on long-latency reflex responses. MOTONEURON EXCITABILITY INDUCED BY RHYTHMIC ARM Perturbations that induced large elbow motion and minimal shoulder motion SWING MOTION IN UPRIGHT STANDING POSTURE were sufficient to elicit or depress long-latency reflexes from shoulder Noritaka Kawashima 1,2,3,4*, Kiyotaka Kamibayashi 4, and Kimitaka monoarticulars. Although we’ve presented our results in term of motion- Nakazawa 4. 1 Institute of Biomaterials and Biomedical Engineering, dependency, the pattern of long-latency reflexes were also appropriate to University of Toronto 2 Lyndhurst Centre, Toronto Rehabilitation Institute 3 counter the underlying perturbing torque. This appropriate mapping of Japanese Society for Promotion of Science 4 Research Institute, National motion to torque is evidence that long-latency reflexes possess a Rehabilitation Center for Persons with Disabil sophisticated representation of limb mechanics, i.e. an internal model. Future studies will determine whether this sophisticated representation can While some evidence of contribution of interlimb neural connection for adapt to novel dynamics as seen during voluntary movements. the generation of locomotive motor output has been suggested, the extent to which upper limb motion can modulate lower limb motoneuronal excitability is not fully understood. In the present study, we aimed to examine how the 404 D125 spinal motoneuronal excitability of the lower limb soleus muscle is MICROSTIMULATION-INDUCED INHIBITION OF FIRING OF modulated with rhythmic upper limb motions during passive standing CELLS IN THE HUMAN SUBSTANTIA NIGRA posture. Soleus H-reflex responses were obtained at eight different motion Lafreniere-Roula M 1, Kim E 1, Hutchison WD 1, Lozano A 2, Hodaie M 2, phase instances during rhythmic arm swing motion in twelve able-bodied Dostrovsky JO 1. 1Dept. of Physiology, Univ. of Toronto, Toronto. 2 Toronto subjects. The amplitude of the H-reflex showed remarkable modulation in Western Hospital, Toronto accordance with the phase of arm motion. It is notable that the H-reflex amplitude during arm swing tended to be larger than that obtained in static Parkinson’s disease (PD) is a movement disorder caused by degeneration (arm rest) condition. Moreover, the degree of the H-reflex modulation tended of dopaminergic cells in the substantia nigra pars compacta (SNpc). Deep to be larger when the arms swung bi-directionally (anti-phase) as compared brain stimulation (DBS) of the subthalamic nucleus (STN) is a viable to the case in which the arms swung in the same direction (in-phase). Two treatment for alleviating tremor in PD patients while avoiding the debilitating possible neural mechanisms can be hypothesized to induce the modulation of dyskinesia caused by long-term use of dopaminergic medication. The the H-reflex: (1) a voluntary neural command which is concurrent with the mechanisms by which DBS works, however, are still unclear. In order to voluntary arm movement (corticospinal pathway); and (2) an interlimb better understand the effects of high-frequency stimulation on local cellular neural pathway which is activated by afferent inputs from the upper limb activity, we compared the effects of stimulation with short trains of high- (interlimb pathway). In order to examine whether the corticospinal frequency, low-current pulses delivered through the recording electrode on excitability modulation involves the above H-reflex modulation, the the firing of cells in the substantia nigra pars reticulata (SNr) and the STN. modulation of the motor evoked potential elicited by transcranial magnetic The SNr is located immediately ventral to the STN from which it receives stimulation (TMS) was evaluated. The results showed a similar modulation excitatory projections. We have examined 142 neurons in the SNr of 33 manner for the H-reflex, suggesting that corticospinal modulation may awake PD patients undergoing stereotactic surgery. A majority (82%) of cells include the H-reflex modulation. These results indicate that there is a neural identified to be in the SNr on the basis of location and spontaneous activity system to modulate soleus spinal motoneuronal excitability in accordance were inhibited by high frequency (200-300 Hz), low current (< 10µA) with the phase of upper arm motions. These results might provide useful stimulation. For example, with 0.5s trains of 2 µA pulses at 200 Hz, the information for how the upper limbs contribute to generating locomotive duration of inhibition ranged from 264 ms to close to 2 sec (avg 600 ±88 ms). motor output in human bipedal walking. Firing of cells located in the STN, just dorsal to the SNr, was typically not inhibited by stimulation with low-current stimulation. This suggests that inhibition of SNr cells by low current, high-frequency stimulation through 403 A152 the recording electrode can be used as an additional criterion to identify the LONG-LATENCY REFLEXES OF SHOULDER demarcation between the STN and SNr, thereby facilitating the determination MONOARTICULARS REFLECT BOTH SHOULDER AND ELBOW of the surgical target. The inhibition observed in SNr neurons may be due MOTION GABA release evoked by stimulation-induced excitation of GABAergic I.Kurtzer*, J.A.Pruszynski, S.H. Scott. Centre for Neuroscience studies, striatal and pallidal afferents. This has been proposed as a mechanism for Queen’s University, Kingston similar microstimulation-induced inhibition observed in the internal globus pallidus (Dostrovsky et al. 2000). Supported by CIHR FRN 42505 While the planar arm model has provided a fertile ground for motor control theories of volitional movement, relatively little is known about reflex coordination in this paradigm. Here we examined whether upper limb 405 D126 reflexes possess a sophisticated representation of limb mechanics as seen RACLOPRIDE-INDUCED MOTOR LEARNING IMPAIRMENT IN during voluntary movements? To test this hypothesis we imposed torque PRIMATES: ROLE OF THE DOPAMINE TYPE-2 RECEPTOR IN perturbations that induced nearly identical displacements at the shoulder joint MOVEMENT CHUNKING INTO INTEGRATED SEQUENCES paired with a range of displacements at the elbow joint (KINARM robot; Maxime Lévesque* 1,2; Marc-André Bédard 1,2; Richard Courtemanche 3; load range ±2Nm; 10 subjects) and recorded reflex activity with surface Pierre J. Blanchet 1,2,4. 1.Centre de Neuroscience de la Cognition, EMG. If reflex activity of shoulder monoarticulars reflected motion at just Université du Québec à Montréal (UQAM), Montréal 2. André Barbeau the spanned/shoulder joint then identical responses would occur across Movement Disorder Unit, Centre Hospitalier Universitaire de Montréal conditions whereas a more sophisticated representation would result in (CHUM), Montréal 3. Center for Studies in Behavioral Neurobiology, different responses for different amounts of elbow motion. This paradigm Concordia University, Montréal; 4. Département de Stomatologie, Faculté revealed a qualitative shift between the early and late reflex activity: the short de Médecine Dentaire, Université de Montréal latency/spinal reflex (20-45 ms) was influenced by shoulder motion only whereas the long-latency/supra-spinal reflexes (50-75ms and 75-100ms) Results obtained in patients with schizophrenia have shown that were increasingly modified by elbow motion. For example, the short-latency antipsychotic drugs may induce motor learning deficits correlated with the reflex of shoulder flexors varied only with shoulder extensor motion whereas striatal type-2 dopamine receptors (D2R) occupancy. Other findings suggest the long-latency reflex was sensitive to shoulder motion but also decreased that the role of the striatum in motor learning could be related to a

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“chunking” process of discrete movements into motor sequences. We placebo-induced DA release in PD. Ongoing work will attempt to extend therefore hypothesized that a D2R blocking substance, such as raclopride, these findings to a larger sample. would affect motor learning by specifically disrupting the grouping of movements into sequences. Two monkeys were first trained to perform a baseline overlearned sequence (Seq A). Then, a new sequence was learned 407 D148 (Seq B) and the overlearned sequence was recalled off-drug (Seq A recall CORTICAL AREAS AND CIRCUITS MEDIATING SOUND OFF-drug). The effect of raclopride was then assessed on the learning of a LOCALIZATION IN THE CAT new sequence (Seq C), and on the recall of the overlearned sequence (Seq A S. Malhotra; J.G. Mellott; S.G. Lomber. Department of Physiology and recall ON-drug). Results showed that performance related to the overlearned Pharmacology, Department of Psychology, Center for Brain and Mind, sequence remained the same in the three experimental conditions (Seq A, Seq University of Western Ontario, London A recall OFF-drug, Seq A recall ON-drug), whether the primates received raclopride or not. On the other hand, new sequence learning was significantly For most mammals the ability to localize a sound in space plays a vital affected during raclopride treatment (Seq C), when compared with new role in the detection and tracking of prey and the avoidance of predators. In sequence learning without the effect of any drug (Seq B). Raclopride- the cat, there are 13 recognized regions of acoustically-responsive cortex. In induced disturbances consisted in performance fluctuations, which persisted this study, we behaviorally examined the individual contributions of each even after many days of trials, and prevented the monkeys from reaching a auditory cortical region to sound localization during both unilateral and stable level of performance. Further analyses also showed that these bilateral reversible deactivation. Cats were trained to attend to a central fluctuations appeared to be related to monkey’s inability to group movements visual stimulus and then approach a 100-ms broadband, white-noise stimulus into single flowing motor sequences. The results of our study suggest that emitted from one of 13 loudspeakers arranged at 15-deg intervals of azimuth. dopamine is involved in the stabilization or consolidation of motor Following training, each cat was bilaterally implanted with cryoloops over performances, and that this function would involve a chunking of movements different regions of auditory cortex. Unilateral deactivation of primary into well-integrated sequences. auditory cortex (A1), the dorsal zone (DZ), the posterior auditory field (PAF), or the auditory field of the anterior ectosylvian sulcus (AES) resulted in severe sound localization deficits confined to the contralateral hemifield, 406 D127 whereas sound localization to positions in the ipsilateral hemifield remained INVESTIGATION OF EXPECTATION AND THE PLACEBO unaffected. Bilateral deactivation resulted in a profound sound localization EFFECT IN PARKINSON’S DISEASE USING HIGH-RESOLUTION deficit throughout both hemifields. Neither unilateral nor bilateral POSITRON EMISSION TOMOGRAPHY (PET) WITH [11C] deactivation of any other regions yielded sound localization deficits. In RACLOPRIDE addition to the cortical control of sound localization, the superior colliculus SC Lidstone*, E Bogusz, K Dinelle, S Blinder, TJ Ruth, AG Phillips, V Sossi, (SC) also plays a key role in accurately orienting the head and eyes to AJ Stoessl. The Pacific Parkinson's Research Centre, Vancouver Hospital acoustic stimuli. Therefore, it is expected that A1, DZ, PAF, and AES must and Health Sciences Centre, University of British Columbia, Vancouver be incorporated into a processing system that transmits signals to the SC. To Brain Research Centre, University of British Columbia, Vancouver TRIUMF, examine this circuitry, biotinylated dextran amine (BDA) or wheat germ University of British Columbia, Vancouver agglutinin-horseradish peroxidase (WGA-HRP) was utilized to reveal the underlying corticocortical and corticotectal acoustic pathways, respectively. Expectation of therapeutic benefit plays a crucial role in the mechanism SMI-32 antibody was used to identify areal boundaries throughout the of the placebo effect in Parkinson’s disease (PD), and has also been shown to auditory cortex and confirm the accuracy of cryoloop placements and tracer increase striatal dopamine (DA) release. We used the ability of [11C] deposits. Deposits of WGA-HRP into acoustically responsive SC layers and raclopride to compete with DA for D2/3 receptors as measured by PET to deposits of BDA into cortical areas PAF and DZ show overlapping cellular investigate DA release associated with expectation strength of levodopa and terminal field labeling in AES. The absence of labeling within A1, DZ delivery in PD patients. Eleven subjects (mean age 61 years) with mild- and PAF from SC deposits eliminates the possibility that the pathway moderate PD (mean Hoehn and Yahr 2.2) underwent 3 PET scans on a high between these areas and tectum is direct. Therefore, these studies of resolution research tomograph (HRRT, Siemens) over 2 consecutive days underlying cortical circuitry suggest that the auditory cortex utilizes a under the following conditions: baseline, following oral administration of multisynaptic circuit to transmit spatial signals to the tectum for accurate 250 mg levodopa, and following placebo administration. Subjects were orienting to an acoustic target. divided into 4 groups based on their verbal instructions, and were told that they had a 25%, 50%, 75% or 100% chance of receiving levodopa when in fact they all received placebo. Emission data were acquired for 60 minutes 408 D128 following bolus injection of 370 MBq [11C] raclopride (RAC) for each scan, ANKLE EXTENSOR ACTIVITY DURING STANDING WAS and reconstructed using Ordinary Poisson-OSEM including attenuation, DRAMATICALLY ATTENUATED WHEN THE BIOMECHANICAL scatter and random correction. Emission data were corrected for motion by NECESSITY OF ANKLE TORQUE WAS ELIMINATED inter-frame realignment with automated image registration. Elliptical and Kei Masani, Noritaka Kawashima, Albert H. Vette, Milos R. Popovic. circular regions of interest were placed on 9 consecutive transaxial slices Rehabilitation Engineering Laboratory, Institute of Biomaterials and (total thickness 10.89 mm), and 6 consecutive coronal slices (total thickness Biomedical Engineering, University of Toronto, Rehabilitation Engineering 7.26 mm) in which the dorsal and ventral striatum were best visualized, Laboratory, Lyndhurst Centre, Toronto Rehab, Japan Society for the respectively, as well as on the cerebellum. RAC binding potentials (BP) Promotion of Science were estimated using a graphical tissue approach (Logan et al. 1996) with the cerebellum as a reference region. Levodopa administration caused a The ankle extensors play a dominant role in controlling the equilibrium significant reduction in RAC BP in the putamen bilaterally (p=0.007and during bipedal quiet standing. Their primary role is to resist the gravity p=0.04) indicating increased DA release. Preliminary analysis indicated toppling torque that pulls the body forward. The activity level of the ankle placebo-induced DA release in the dorsal and ventral striatum in groups with extensors is modulated by the biomechanical necessity of ankle torque, i.e., an expectation strength of 50% and greater. In addition, patients who when the body is located in the forward position, the required ankle torque is perceived benefit following placebo administration tended to have increased large and thus, the muscle activity becomes large. In previous studies that DA release in the dorsal striatum as compared to those who felt no benefit. investigated the neural circuits controlling the muscle activity, a back rest This dissociation was not seen in the ventral striatum, supporting our earlier supporting the slightly rotated body against gravity has been frequently used results (de la Fuente-Fernandez et al. 2002). These results support striatal

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to diminish the muscle activity in standing posture. However, considering the activity in females during visuomotor skill performance (Gorbet et al., abovementioned role of the ankle extensors in standing posture, it is believed 2007(in press)). Similarly, distinct cortical networks for complex visuomotor that eliminating the need of the ankle torque by providing a backward torque control may underlie the effects of experience observed in both initial instead of modifying the standing posture by means of the back rest should performance and learning of the unimanual task. be more relevant with respect to the attenuation of the activity. The purpose of this study was to demonstrate that the ankle extensor activity was dramatically attenuated when the biomechanical necessity of ankle torque 410 D130 was eliminated. Ten healthy adults stood on a force plate. Electromyograms THE EFFECT OF DIFFERENT EXPOSURES ON MOTOR in the ankle extensors, the ankle angle and torque were measured. In the first LEARNING trial, the subjects stood naturally. In the second trial, the subjects were Jason L. Neva & Denise Y.P. Henriques. School of Kinesiology and Health supported below both patellas by a ground-fixed device. The device was Science & Centre for Vision Research, York University, Toronto located at a height level that sufficiently compensated the gravity toppling torque. The whole body was supported via this small device instead of Learning new motor skills and operating off a learned motor program is an several braces so that this manipulation did not distract each subject's natural integral part of our everyday lives. In order to properly consolidate a new posture. In particular, the subjects felt that they were standing naturally, motor program the brain requires a certain amount of practice to the being unaware of any changes in the muscles. As a result of this manipulation particular stimuli. It has been shown that the brain can learn to correct for of body support, the muscle activities of the ankle extensors were altered visual feedback when performing reaching movements. However, in dramatically attenuated and approximately the same as during the resting order to properly learn, the brain must receive repeated exposure to a small condition, with the ankle angle set constant between the trials. Thus, we number of target locations. As the number of training targets increases, the demonstrated that, when the biomechanical necessity of ankle torque was rate of learning subsequently decreases, as does the saturation of the sufficiently eliminated, the ankle extensor activity became negligible for adaptation. After adaptation has occurred the brain can transfer this skill to keeping the natural standing posture. Although the neural mechanism of this reach properly to target locations that have not been practiced. But we are phenomenon is unclear at the moment, considering the minimum limited in our ability to generalize this learned skill to novel target locations manipulation in the experimental setup compared to the bracing of the joints, (Krakauer et al., 2000). Is the brain able to adapt to altered visual feedback this experimental model could be advantageous in investigating the neural through different training conditions? For instance, can the brain learn when mechanism of standing. practicing only once to each target in an array? In this study we investigated the question of how much exposure is required to accurately reach to visual targets under altered visual feedback, i.e. a 30º rotation. We also examined 409 D129 the extent to which this learning could transfer to target locations not EXPERIENCE- AND SEX-RELATED DIFFERENCES IN THE specifically trained to. Twenty-seven subjects adapted to two separate INITIAL PERFORMANCE AND LEARNING OF NOVEL training conditions, both under the visual distortion: one with repeated VISUOMOTOR TASKS reaches to a small number of targets (Multiple exposure) and one with a K.L. McCullough, L.E. Sergio. School of Kinesiology & Health Science, York single reach to many different targets (Single exposure). In the Multiple University, Toronto exposure condition, subjects trained to the same 4 target locations repeatedly. In the Single exposure condition, subjects trained to 81 different target Experience and sex-related differences in bimanual coordination have locations only once. After learning to reach accurately subjects were then been found in skill performance and in underlying brain activity patterns tested, under the same 30º rotation, to targets that they were not previously (Bryden et al., 2005; Haslinger et al., 2004). Established sex-based exposed to assess the extent of generalization. We found there is very little differences in neural connectivity (Marion et al., 2003) and an elite-athlete's difference in learning rate between the two different exposure conditions. extensive experience performing both practiced and novel complex This suggests the brain is able to learn a visual rotation similarly while being visuomotor skills would seem to account for these behavioural and functional exposed to varying targets a single time and that repeated reaches to the same differences. We related visuomotor skill performance to sex and athletic target locations is not necessary. We also found the generalization of learning experience in order to indirectly gain insight into the neural processes that to new target locations between the two conditions to be very similar. This underlie this advanced level of eye-hand coordination. In our assessment of again suggests the brain can consolidate and apply this learned motor skill to initial performance, elite-level male and female hockey players, recruited new situations through both of our exposure conditions. from the National Hockey League (NHL) and the National Women's Hockey League (NWHL), were compared to control subjects on novel bimanual and unimanual visuomotor tasks. A modified washer-peg bimanual task required 411 D131 coordinating alternating hands. An ANOVA on bimanual task times revealed BI-DIRECTIONAL SYNAPTIC PLASTICITY IN PALLIDUM OF a significant main effect of sex. Post-hoc analyses revealed that females CERVICAL AND GENERALIZED DYSTONIA PATIENTS performed more quickly relative to males, with elite females significantly I.A. Prescott1, J.O. Dostrovsky1, M. Hodaie2, A.M. Lozano2, W.D. outperforming all other groups. In the unimanual task, subjects navigated a Hutchison1,2. 1Department of Physiology, Faculty of Medicine, cursor around virtual pylons by manipulating a robotic arm in a three- 2Department of Surgery, Division of Neurosurgery, University of Toronto & dimensional acceleration-dependent force field. Analyses of the inital Toronto Western Research Institute and Krembil Neuroscience Centre, performance of this task revealed a significant main effect for experience, Toronto with the elite males significantly outperforming all other groups. Interestingly, the initial performances of both elite and non-elite females on Aberrant forms of synaptic plasticity may underlie the pathophysiology this task were virtually identical. We examined this result by extending the of dystonia, a movement disorder characterized by sustained muscle unimanual testing protocol to examine the effects of experience on the ability contractions and abnormal postures. The internal segment of the globus of elite and control females to learn the unimanual task. While elite females pallidus (GPi) is the primary somatomotor output of the basal ganglia and learned the task quickly and achieved a higher level of performance overall, tonically inhibits corticothalamic and brainstem premotor circuits. The the non-elite females achieved significant learning throughout the entire task. remarkable efficacy of GPi high frequency stimulation (HFS) for surgical These behavioral differences suggest both sex-related and experience-related therapy of dystonia suggests that aberrant plasticity at the output of basal differences in the neural processes that underlie bimanual and unimanual ganglia may be involved. Synaptic plasticity in GPi was induced by HFS in coordination. These data may reflect recent findings of increased bilateral awake patients with generalized (whole body) and cervical (neck only)

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dystonia. Dual microelectrode wide band (10 - 5kHz) recordings were made expansion of time. However, most previous studies used complex visual in one cervical and one generalized dystonia patient undergoing implantation shapes, which made it difficult to identify specific brain mechanisms that of deep brain stimulation electrodes in the GPi. Evoked field potentials may underlie this perceptual effect. Therefore, we were interested to know (eFPs) were recorded while stimulating with single pulses (50uA, 0.3 ms if this subjective expansion of time can occur for a low-level visual stimulus biphasic pulses, 1 Hz) from the second electrode located about 1 mm away such as linear motion. Because visual cortical neurons are stimulated by a at the same dorsoventral level. After establishing a stable baseline, standard preferred direction of motion, we asked how does this contrasting population tetanizing HFS (100 Hz, 2 s trains repeated 4 times at 10 sec) was performed activity contribute to our perception of time. Using a random dot and the effects on eFP amplitudes were measured for up to 5 minutes. Then kinematogram (75% coherent motion pulses of 200 ms separated by random low frequency stimulation (LFS, 20uA, 2 – 5 Hz, 10 – 20 s) was given motion of 400 ms), subjects reported the duration of an oddball motion through the recording electrode to test for post-synaptic depression of the direction that followed a series of standard motion pulses. The oddball eFP amplitudes. A final HFS confirmed the range of bi-directional plasticity. motion pulse moved in one of five directions relative to the standard pulses HFS potentiated eFPs by similar degrees in both groups (gen. by 65%, cer. and varied in duration relative to the duration of the standard pulse trains. by 71%), while LFS depressed eFPs in generalized dystonia to a much The resultant psychometric curves show different magnitudes of time greater extent than in cervical dystonia (eFP amplitude ranges of 106% and expansion for different oddball directions. In addition, the results suggest that 19% respectively). The final HFS potentiated both groups to pre-LFS levels. changing the expectancy of an oddball direction based on the pattern of Patients with cervical and generalized dystonia demonstrate similar induction standard pulses affects the subjects’ perception of time. Together, these but different reversal of plasticity, indicating an asymmetric bi-directional results propose a link between neuronal activity in areas of visual cortex that plasticity in GPi neurons. These preliminary results suggest that more severe encode a low-level motion stimuli and our subjective perception of time. forms of dystonia are associated with greater post-synaptic depression of GPi Supported by operating grants from CIHR and NSERC. neuronal responsiveness.

414 D134 412 D132 VISION DOES NOT RECALIBRATE OUR KINESTHETIC SENSE RAPID EMG AND CORTICAL RESPONSES TO PERTURBATIONS OF HAND POSITION ARE MODIFIED BY VISUO-SPATIAL GOALS Eric A Shikatani, Teser Wong, Denise YP Henriques. School of Kinesiology J.A.Pruszynski 1*; I.Kurtzer 1; S.H.Scott 1,2. 1. Centre for Neuroscience and Health Science, Centre for Vision Research, York University Studies, 2. Dept. of Anatomy and Cell Biology, Queen's Univ, Kingston During motor learning, multiple senses interact to produce desired Previous studies have shown that upper-limb reflexes are task-dependent, movements. When faced with inconsistent sensory feedback, people however, the extent of reflex flexibility remains unknown and largely subconsciously use context and modality specific weightings to determine unlinked to theories of motor function. To further explore the task- the optimal use of this sensory information. We know that vision plays a dependency of reflexes, we have created a multi-joint paradigm where dominant role in motor learning and can even override other senses: if the human or non-human primates respond to sudden arm perturbations by hand is represented by a cursor and this visual feedback is rotated 30˚ quickly placing their hand into a visually-defined target. Subjects were counterclockwise (CCW), people will adapt their movements to move up and shown a target located medial or lateral to their hand while they countered a to the right in order to produce seen movement of the cursor straight forward, constant background load. After a random hold time, a step-torque displaced despite conflicting visual and kinesthetic information. Even in complete the hand either into the target area (requiring no correction) or out of the darkness, people continue to make these adapted movements due to target area (requiring rapid correction). Hence, we were most interested in the miscalibration of the arm motor system. Currently it is not known whether differences across muscle/cortical responses for the same imposed the visual recalibration of the arm motor system also recalibrates the perturbation but different spatial target locations. Human EMG responses kinesthetic sense of hand position. Here, we investigated whether learning to recorded from arm flexors and extensors exhibited a three-peaked series of reach with the left hand with altered visual feedback of hand position reflex activity with increasing sensitivity to target position. The earliest (visuomotor adaptation) affected subjects’ ability to locate their unseen left reflex responses (20-50ms) were determined entirely by perturbation hand with their right hand. To measure subjects’ kinesthetic sense of left direction regardless of target position. In contrast, responses between 50- hand position, we used a localization task where subjects grasped a robot 75ms were evoked by perturbation direction but scaled by target position and manipulandum underneath a tinted surface so their left hand was not visible. responses from 75-100ms were often evoked or suppressed entirely by target The robot was programmed to restrict movements to a single angle along a position. Motor cortical (M1) neurons recorded from non-human primates ‘kinesthetic’ wall. Subjects would move their unseen left hand to the end of reveal that even the earliest cortical responses (20-50ms) are modulated by this wall, and then point to its felt position with their right hand. We found target position, indicating that M1 processing is influenced by task goals and that subjects generally overreached targets (unseen left hand) along the suggesting that M1 activity underlies the task-dependent EMG differences direction of extent. We then fitted confidence ellipses to reaches for each observed in humans. Future experiments will explore whether rapid EMG target and found that all ellipses were oriented towards the subject. For the and cortical responses are tuned to more complex visuo-spatial features. visuomotor adaptation, subjects adapted their left hand to rotated visual feedback of 30˚ CCW, which was introduced gradually so that they wouldn’t be aware of this adaptation. Following adaptation, we retested 413 D133 subjects’ kinesthetic sense of left hand position, and found that there was no THE PERCEPTION OF TIME IS INFLUENCED BY LOW-LEVEL difference in localization errors, suggesting that while vision may recalibrate CHARACTERISTICS OF VISUAL MOTION the motor system of the arm to ensure consistency across senses, it does not Navid Sadeghi Ghandehari, Sameer Apte, Erik P Cook. Department of recalibrate arm kinesthesia. However, we found that the orientations of the Physiology, McGill University ellipses were significantly different, suggesting that following adaptation, the trajectories taken to targets may have changed. Our perception of the duration of a visual stimulus does not always corroborate with the actual time the visual stimulus is presented. It has been shown that an oddball stimulus observed after a train of repeated stimuli appears to be longer in duration. This effect is referred to as the subjective

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415 D135 can consolidate rapidly if the learning process is stopped. The process of UPDATING SPATIAL MEMORY ACROSS DIFFERENT EYE consolidation may depend on the test frequency. MOVEMENTS FOR ARM MOTOR CONTROL Aidan A. Thompson & Denise Y.P. Henriques. School of Kinesiology and Health Science & Centre for Vision Research, York University, Toronto 417 D137 MOTOR SEQUENCE LEARNING AND D2 RECEPTORS We use visual information about our surrounding environment in order to Pierre-Luc Gilbert Tremblay (1) Marc-André Bédard (1,2) Pierre J Blanchet generate movements to objects within that environment in our daily lives. It (1,2,3). 1. Cognitive Neuroscience Center (CNC), Université du Québec à has been well demonstrated previously that when an object is selected as the Montréal (UQAM), Montréal 2. André-Barbeau Movement Disorders Unit, target of an action, its location is stored in an eye-fixed frame (Henriques et Hotel-Dieu, Montréal, 3. Department of Stomatology, Dental Medicine, al, 1998). Given that the eyes move frequently (i.e., ~ 4 -5 times per second), Université de Montréal, Montréal these eye-fixed spatial representations must be updated for the arm-motor system. Other studies have shown that eye-fixed spatial updating applies also Motor learning disturbances have been shown in clinical conditions to targets at different distances (Medendorp et al., 2002), to tactile and characterized by a striatal dopamine dysfunction, such as in Parkinson’s auditory targets (Pouget et al., 2000), and to implicit targets defined by disease or patient with schizophrenia treated with antipsychotic agents. In expanding motion patterns (Proljac & van den Berg, 2003). But spatial monkey (Cebus Apella), our group (Lévesque et al., 2007) has shown some updating for arm control has not been demonstrated for other types of eye specific motor learning deficits following the systemic administration of movements (i.e., smooth-pursuit). The goal of our study is first to determine raclopride, a selective D2-receptor antagonist. These deficits were mainly if the remembered locations of visual targets are updated following a smooth- characterized by a lack of stabilization that is persistent fluctuations of pursuit eye movement as they have been found to following a saccade. And performance from trial to trial, suggesting a difficulty in consolidating the second, to determine if visual information plays a role in estimating eye motor sequence. Moreover, these fluctuations were found to be related to a movements for updating spatial memory. Participants (N=8) pointed to difficulty in chunking new movement components to old and well remembered targets under three separate conditions. In the first, participants established ones. These specific deficits were not observed following the viewed a briefly flashed target and then looked to one of seven locations after administration of a D1-receptor blocking agent. In order to further assess the the target disappeared, by either making a saccade or a smooth-pursuit. They role of dopamine in the chunking process of motor sequence learning, we then pointed to the remembered location of the original target. The second verified the reversibility of the raclopride (0,05 mg/kg) induced deficit, by condition was identical to the first, but, had a series of dots above and below administering sumanirole (1 mg/kg), a highly selective D2 agonist agent. the stimulus which moved in either the same or opposite direction as the Two monkeys were trained to execute an overlearned sequence, that was eyes. The third condition was similar, but, required no eye movements, recalled under no drug effect (baseline), under raclopride effect, and under allowing us to glean the impact of the moving background on estimating eye sumanirole effect (administered 15 minutes after raclopride). The same was motion. Participants always pointed in complete darkness without visual also done with a new sequence that has to be learned without drug (seq 2), feedback. We found no differences in pointing responses following saccades under the raclopride effect (seq 3), and under sumanirole (seq 4). Results and smooth-pursuits, but found that when the background moved in the showed a raclopride-induced disturbance for the new sequence learning (seq opposite direction of a smooth-pursuit, pointing responses did differ from 3) but not for the overlearned one (seq 1). As previously demonstrated those made when the background moved in the same direction as the eye or (Lévesque et al., 2007), these deficits where characterized by persistent was absent. This suggests that the location of a visual target is updated fluctuations of performance from trial to trial (even after hundreds of trials), following a smooth-pursuit movement of the eyes, and that visual and by a deficit in chunking a new movement to an old and well established information plays a role in estimating eye movements for updating spatial one. The reversibility of these effects with sumanirole will be presented. memory when smooth-pursuits are made but not when saccades are made. 418 D138 416 D136 GRASPING THE FUNCTION OF TOOLS: FMRI SUGGESTS THAT RAPID CONSOLIDATION OF MOTOR MEMORY IN THE THE VENTRAL BUT NOT THE DORSAL STREAM CODES THE VESTIBULO-OCULAR REFLEX FUNCTIONAL SIGNIFICANCE OF FAMILIAR OBJECTS H. K. Titley 2, R. Heskin-Sweezie 2, J.-Y. J. Chung 2, C. D. Kassardjian 1, F. Kenneth F. Valyear and Jody C. Culham. University of Western Ontario, Razik 1, and D. M. Broussard 1,2,3. 1 Division of Fundamental London Neurobiology, Toronto Western Research Institute, University Health Network 2 Department of Physiology, University of Toronto 3 Division of When grasping-to-use a familiar tool we often make use of stored Neurology, Department of Medicine, University of Toronto information about the functional identity of the tool in order to guide our actions. At present, exactly which brain areas play an important role in Newly acquired motor memory is relatively labile, and susceptible to representing this information is poorly understood. For example, is disruption, but can become more resilient through consolidation. We information regarding the functional significance of familiar objects stored investigated the time course of consolidation of motor memory in the within those areas mediating object-directed actions or does this information vestibulo-ocular reflex (VOR). Learned decreases were induced in the gain stem from other areas of the brain? During functional magnetic resonance of the VOR by 60 minutes of passive sum-of-sines rotation of cats wearing imaging (fMRI), participants viewed short movies depicting different types telescopic miniaturizing lenses. We then attempted to disrupt the new of grasping actions made towards familiar tools. In one condition, the tool memory using rotation in darkness. If rotation in darkness immediately was grasped appropriately such that its function could be performed without followed learning, disruption was successful; the VOR gain increased further postural adjustments (e.g. a fork was grasped by the handle with the towards its pre-learning value. For 2-Hz rotation, if immediately after tines facing away from the actor). In the other condition, the tool was grasped learning the cat spent an intervening 30- or 60-minute period stationary inappropriately such that its function could not be performed without further without form vision (“neutral period”), the subsequent disruption was postural adjustments (e.g. a fork was grasped by the handle with the tines considerably less effective, suggesting that memory had consolidated. facing toward the actor). We hypothesized that the viewing of functionally However, at 0.5 Hz, we did not consistently observe consolidation on this appropriate grasping actions would resonate more strongly with those areas short time scale. We conclude that the newly formed memory in the VOR is involved in the processing of object function. Our results showed initially labile, as they are in other systems. However, VOR motor memory significantly stronger activity for the viewing of functionally appropriate as

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compared with inappropriate grasping actions within several brain areas HT and dopaminergic (DA) axons and terminals. Human basal ganglia are previously implicated in higher-level object perception. In contrast, areas principally innervated by 5-HT axons that emerge from the dorsal and implicated in the control of object-directed actions did not distinguish median raphe nuclei. These axons formed distinct fascicles that fragmented between the two conditions. These findings suggest that information about themselves as they penetrate the decussation of the superior cerebellar the functional significance of objects is stored within areas specialized for peduncles. They regroup within the ventral tegmental area and ascend along object perception and not within areas specialized for object-directed action. the medial forebrain bundle immediately below the DA ascending fibers. At Thus, object utilization based on stored knowledge of object function must regular intervals along their ascending course, axons detach themselves from involve a complex interplay between systems specialized for object the main bundle and sweep laterally to arborize within the various basal perception and those specialized for the control of actions. ganglia components. The 5-HT innervation of these nuclei is highly heterogeneous; the caudate nucleus is poorly innervated by comparison to the putamen and globus pallidus, whereas the 5-HT innervation of the 419 D139 subthalamic nucleus displays a mediolateral decreasing gradient. At variance ROLE OF HUMAN PPC IN THE INTEGRATION OF INITIAL with the situation in monkeys, 5-HT terminals in the human striatum are not HAND POSITION INFORMATION INTO THE REACH PLAN distributed according to the patch/matrix organization and 5-HT axons do not Michael Vesia1,2,5*, Xiaogang Yan1,2, Denise Y. Henriques 1,2,5, Lauren E. form bands at pallidal level. This study has delineated the pattern of the 5-HT Sergio 1,2,3,5, J. D. Crawford 1,2,3,4,5. Centre for Vision Research 1, innervation of human basal ganglia, the knowledge of which is essential to Canadian Institutes of Health Research Group on Action and Perception 2 correctly interpret the complex neurochemical changes that occur within and Departments of Psychology 3, Biology 4, and Kinesiology and Health these nuclei in neurodegenerative diseases. [Supported by grant MT-5781 of Science 5, York University, Toronto the Canadian Institute for Health Research].

Lesion and transcranial magnetic stimulation (TMS) studies in humans implicate the posterior parietal cortex (PPC) for the planning and control of 421 D141 actions. We previously reported that TMS reveals a hemispheric asymmetry THE PERCEIVED TIMING OF THE ACTIVE AND PASSIVE in the early stages of the putative spatial processing in the human PPC. COMPONENTS OF TOUCH Moreover, we postulated that this brief TMS pulse modifies the output of the Rebecca Winter*, Marta Gozdzik right PPC in motor coordinates, rather than modifying the upstream visual coordinates of the memory representation (Vesia et al., J. Neurophysiol, Tactile stimulation usually occurs as a result of an active movement (e.g., 2006). Alternately, TMS could have altered the state estimate of the initial reaching out to touch a surface) and a passive sensation (feeling the surface hand position. To test this hypothesis, we investigated the memory-guided against the skin). The brain knows about the active component (a motor pointing accuracy in six subjects during TMS of the left and right PPC while command) before it has even occurred through efferent copy, while the varying visual information of the effector. We tested four conditions: 1) passive component must be processed. Since the timing of the two initial and final vision of hand positions (IFV); 2) mid and final vision of components are very different, determining the time of the touch requires hand positions (MFV); 3) final vision of hand position (FV); and 4) full either backwards calculation from the passive sensation, and/or worked vision of hand position (IMFV). In accordance with previous findings, forward from the active motor command. In order to determine which subject’s pointing errors and biases varied as a function of stimulation site process is responsible for the perceived temporal properties of touches, we during the FV condition - left parietal stimulation significantly increased varied the relative delay between the two touch signals and determined the endpoint variability, while right parietal stimulation produced a significantly delay regarded as simultaneous. Since the perception of simultaneity systematic leftward directional shift in both visual fields during the FV between two stimuli can be affected by repeated exposure to asynchronous condition. In addition, these systematic pointing errors and biases presentation, we exposed subjects to an active key press with a passive touch significantly decreased during the IMV, IFV, and IMFV conditions. These delayed by 250 ms. This caused subjects to accept a wider range of inter- data causally demonstrate the important role of the human PPC in the stimulus delays as simultaneous; was this due to altering the active or passive formation of internal ‘forward’ state estimates that may be used to component? We tested the two components separately against a common recursively plan and control visually-guided reaching movements. stimulus. The results are discussed in the context of simultaneity constancy during the perception of active movement.

420 D140 SEROTONINERGIC INNERVATION OF HUMAN BASAL 422 D142 GANGLIA ACTIVE AND PASSIVE ESTIMATES OF FELT HAND PATH ARE MJ Wallman, A. Parent. Anat & Physiol Dept, Laval Univ, Quebec City NOT RECALIBRATED BY VISION Teser Wong*, Christopher Hideg, Tina Soares, Eric A Shikatani and Denise Serotonin (5-hydroxytryptamine, 5-HT) occurs in most major brain YP Henriques. School of Kinesiology and Health Science, Centre for Vision structures and is involved in various state-dependent activities, and in a wide Research range of cognitive and behavioral functions, including the control of movement. The basal ganglia are motor-related structures that receive a Motor control relies on multiple sources of information. For instance, to particularly dense 5-HT innervation, but the role that this neurotransmitter estimate the location of our hand, the brain uses both vision and body- plays in this complex set of nuclei in both normal and pathological states in position sense. And performance is better when more than one sensory poorly known. Although the 5-HT innervation of basal ganglia has been the modality is present, i.e., we can reach more accurately when we can both see subject of detailed studies in rodents and monkeys, the pattern of 5-HT and feel our hand. But in cases of sensory conflict, that is when sensory innervation of human basal ganglia has received very little attention. We modalities disagree, one sense may reshape a motor system to ensure online have addressed this issue by applying an immunohistochemical approach to consistency across the senses. Although the online consistency is important postmortem human brain material gathered from normal individuals. We for controlling and adapting movements, it may be that the recalibration that used specific antibodies directed against the 5-HT transporter (SERT) and the produces this consistency does not persist when the conflict no longer exists, 5-HT synthesizing enzyme (tryptophane hydroxylase) to visualized, as in the case when the dominant sense (e.g., vision) is removed. In this respectively, axons and cell bodies that contained 5-HT. Some section were experiment, we tested whether vision merely overrules kinaesthesia or also immunostained for tyrosine hydroxylase to compare the location of 5- whether it recalibrates our felt sense of hand path. We adopted a task

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developed by Henriques & Soechting (2003) for measuring kinesthetic 424 D144 sensitivity of hand path geometry. We began by mapping out subjects’ EFFECTS OF GESTATIONAL SEROTONIN DEPLETION ON sensitivity to circles by having them actively trace elliptic contours while FUNCTIONAL DEVELOPMENT OF PAIN DESCENDING gripping the handle of a programmable robot and estimate whether the PATHWAYS ellipses are tall or wide. This was followed by a visual adaptation task where M. Lafrance1* D.J. Denis1,2, G. Roussy1, N. Beaudet1, S. Marchand2 and subjects learned to move their unseen hand along an elongated ellipse to P. Sarret1*. 1Dept. of Physiology and Biophysics, 2Dept of Neurosurgery, transport a cursor along a circle. We then quantify whether this sensitivity Faculty of Medicine, Univ. of Sherbrooke, Sherbrooke, PQ, Canada becomes biased after motor commands are calibrated by false visual feedback. Our data show that subjects’ sense of circularity does not become Serotonin (5-HT) regulates cell differentiation during development of the biased in the direction of the distortion. That is, after learning to make tall central nervous system. The aim of this study was therefore to determine the elliptic hand paths to follow a seen circular path, they did not mistake tall effects of 5-HT depletion, on postnatal pain sensitivity, during neurogenesis ellipses for circles. In a second experiment, we tested whether subjects’ sense of the brainstem nuclei involved in descending pain modulation. Gestational of circularity is even more vulnerable to visual calibration when subjects rat Sprague-Dawley dams were injected with para-chlorophenylalanine judge whether ellipses are tall or wide after having their hand passively (pCPA, 400 mg/kg, ip) at embryonic day (E) 10 and E14 to deplete serotonin moved by the programmed robot, given that estimates of passive hand during neuronal proliferation of descending pathways and axonal migration, motion are less accurate than those of active motion. Our results show that respectively. Neuronal proliferation was assessed injecting bromo- subjects’ sense on passive hand motion remained did not change after deoxyuridine (BrdU) at E12. Offspring acute pain was tested with thermal adapting to false visual feedback. The above results are consistent with our plantar test, measuring fore- or hindpaw withdrawal latency at postnatal day pervious experiment measuring the effect of visual adaptation on kinaesthetic (P) 7, P14 and P21. Formalin test was used at P25 to evaluate the effects of sensitivity for different hand path geometries (i.e. tilt and curvature), and 5-HT depletion on persistent pain. Nociceptive responses to formalin strongly demonstrated that subjects’ kinaesthetic sensitivity does not administration were divided in 3 phases: acute (phase I), interphase and late recalibrate after false visual feedback. (phase II). Immunohistochemistry staining was performed for tryptophan hydroxylase, dopamine beta-hydroxylase and BrdU, coupled with unbiased stereology to count immunoreactive neurons in the raphe dorsalis, raphe 423 D143 magnus and locus coeruleus. Control pups tested for thermal pain were less MOTOR CORTEX CORRELATES OF POSTURE AND sensitive for the forepaw than the hindpaw only at P7 and the response MOVEMENT IN INSTRUCTED-DELAY REACHING TASK IN latency increased at P14 and P21 compared to P7. Following pCPA injections CATS at E10, the forepaw becomes less sensitive than the hindpaw at P14. When S.Yakovenko*; T.Drew. Dept. Physiologie, U. de Montreal, Montreal pCPA was injected at E14, latency responses of both paws increased in comparison to controls at P14. pCPA treatments did not alter acute thermal Reaching movements in cats are preceded by anticipatory postural pain responses at P21. In formalin test, pCPA E10 pups pain score was lesser adjustments (pAPA) to compensate for movement-evoked postural than controls in phase II and males showed less pain in interphase. No disturbances. During reaching the supporting limbs also produce postural significant change was observed for any E14 pCPA groups. An increase in adjustments accompanying the movement (aAPA) to ensure further postural immunoreactive neurons, by stereology analysis, will support the nociception stabilization of body. Thus, the neural system responsible for the control of decrease observed in behavioural assessments. In conclusion, targeting reaching integrates both movement and posture-related signals to coordinate proliferation period of descending pain pathways with gestational 5-HT the execution of the movement. In the present study, we tested the hypothesis depletion diminishes both acute and tonic pain. However, 5-HT depletion that the motor cortex contributes not only to the execution of the movement, during axonal migration only reduces acute pain. Since changes in thermal but also to the APAs that precede them. We trained three cats to perform a pain were seen only at P14, we suggest that the decrease in acute nociception task in which they were required to stand quietly and then reach to and press caused by 5-HT depletion results from the post-natal maturation of the on a lever with either the left or right forelimb for a food reward. Following descending pathways. Supported by CIHR, CRSNG and FRSQ. an instruction tone of random duration (0.5 - 1.5 s), the cats reached forward and depressed the lever with the instructed limb. During the task single neurons were recorded from the motor cortex with conventional 425 D145 microelectrodes mounted in a mechanical microdrive attached to the MULTISENSORY CONVERGENCE IN THE PERIPHERAL FIELD cranium. Electromyographic activity (EMG) was recorded from the major REPRESENTATION OF PRIMARY VISUAL CORTEX OF THE CAT contralateral forelimb muscles and selected muscles of the hindlimbs and the Amee J. Hall, Jeffrey G. Mellott, Stephen G. Lomber. Department of ipsilateral forelimb. Kinetic and kinematic parameters were recorded using Physiology and Pharmacology, Department of Psychology, and Centre for force sensitive platforms and a motion capture system. We recorded 219 Brain and Mind, University of Western Ontario, London, Ontario, Canada motor cortical cells of which 82% were pyramidal tract neurons (PTNs). The database of cells included 38% (84/219) that showed an initial change in Sensory systems do not operate in isolation and must have the ability to activity that was better related to the Go signal (stimulus) than to the influence each other. On a behavioral level, we have been examining the movement produced by that stimulus. All of these neurons had a subsequent influence of auditory cortex on basic visual functions. Therefore, we are period of activity that was better correlated to the movement. In a previous interested in identifying possible pathways that may serve to mediate these study (Schepens and Drew 2004) we have argued that cells in the brainstem interactions. In adult cats (>6 months), sources of auditory cortical reticular formation with activity time-locked to the Go stimulus contribute to projections to primary visual cortex (areas 17 & 18) were studied using the production of the APAs preceding movement. In agreement with this injections of wheat germ agglutinin conjugated to horseradish peroxidase view we found that the discharge activity of the Go-related cells in this study (WGA-HRP) into area 17 or areas 17 &18. Two groups of animals were was also strongly related to the temporal characteristics of the force and studied. In the first group, multiple injections into the representations of both EMG changes occurring during the pAPA. These results provide support for the central and peripheral visual fields were made on the vertical meridian the view that the motor cortex contributes to the anticipatory postural representation along the border between areas 17 and 18. In agreement with adjustments that precede reaching in addition to the movement itself. previous studies, characteristic patterns of cell body labeling were identified in extrastriate visual cortex (areas PMLS, PLLS, AMLS, 19, 20, & 21) and the visual thalamus (LGN, MIN, & LPl), thus confirming the efficacy of the tracer injections. Labeled neurons were also identified in the visual area of

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the anterior ectosylvian sulcus (area AEV). In auditory cortex, of the four observed during saccades to handheld targets, suggesting that the saccade tonotopically-organized regions, labeling was identified in the supragranular generator does not have a complete internal model of limb mechanics. Here, layers of the posterior auditory field (PAF). Little or no labeling was evident we tested this hypothesis by measuring saccades to targets held in both the in the primary auditory cortex (AI), the anterior auditory field (AAF), or the left and right hand, varying the initial posture of the body and tilting head ventral posterior auditory field (VPAF). Furthermore, little or no labeling was position leftward or rightward. All experiments were done in a dark room. identified in the remaining nine generally-recognized regions of auditory Saccades and hand movements were measured using search coils and an cortex. In the second group of cats, single injections were made into the Optotrak device respectively. 8 radial target locations on a frontally placed central or peripheral field representations of area 17 or areas 17 &18. table were used in five different paradigms: 1) right hand (body and head Between the two groups, while similar labeling patterns were identified in centered); 2) left hand (body and head centered); 3) right hand (body left); 4) visual cortex, labeled cells were only identified in PAF following injections right hand (head roll contra-clockwise); 5) right hand (head roll clockwise). into regions of primary visual cortex representing peripheral, but not central, The anisotropy of saccade errors reversed symmetrically with right vs. left visual field representations. Therefore, in auditory cortex, while no hand, and tilted with body left rotation, but did not change with head roll projections originating in A1 could be found to terminate in primary visual rotations. This supports our hypotheses that the anisotropy of the hand- cortex, projections were identified from non-primary PAF. Furthermore, guided saccade errors is mainly due to the incomplete compensation in the these acoustic projections specifically terminate in the peripheral field saccade generator for the anisotropy of limb mechanics. representations of primary visual cortex.

426 D146 TECHNIQUES IN NEUROSCIENCE VISUAL AND TACTILE INTERACTIONS DURING VISUALLY GUIDED POINTING *Brendan F Morrissey, Liana E Brown, Melvyn A Goodale. Brendan F 428 B302 Morrissey12, Liana E Brown1, Melvyn A Goodale12. 1 Department of APPLICATIONS OF FUNCTIONAL NEAR INFRARED Psychology, The University of Western Ontario; 2 Department of Physiology SPECTROSCOPY (fNIRS) TO PSYCHIATRIC AND and Pharmacology, The University of Western Ontario NEUROLOGICAL DISORDERS Farzin Irani, Steven M. Platek, Scott Bunce, Anthony C. Ruocco and Douglas Electrophysiological studies have reported the existence of visual-tactile Chute. Drexel University bimodal cells in parietal, premotor, and subcortical areas in the macaque monkey. Many of these cells have tactile receptive fields on the hand and Functional near-infrared spectroscopy (fNIRS) is an emerging functional face with overlapping visual receptive fields that extend into nearby space. neuroimaging technology that offers a relatively non-invasive, safe, portable, The additional recruitment of bimodal cells by visual stimuli presented near and low-cost method of both indirect and direct monitoring of brain activity. the hand may account for human behavioural findings of enhanced visual Most exciting is its potential to allow more ecologically valid investigations processing of stimuli near the hand. This study investigates whether areas on that can translate laboratory work into more realistic, everyday settings and the hand with higher tactile receptor densities (glabrous skin of the palm) clinical environments. The purpose of this poster is to acquaint clinicians and benefit from greater bimodal cell representation relative to areas with lower researchers with the unique and beneficial characteristics of fNIRS by tactile receptor densities (hairy skin on the back of the hand). We predicted reviewing the relative merits and limitations of this technique vis-à-vis other that such a difference in bimodal cell representation would result in better brain-imaging technologies such as functional magnetic resonance imaging visual processing of stimuli near areas with higher densities of tactile (fMRI). Cross-validation efforts between fMRI and fNIRS and the possible receptors compared to areas with lower densities of tactile receptors. We hesitations for its deployment in clinical research and practice will be tested this idea by asking healthy undergraduates to perform rapid pointing discussed. Finally, because there is no comprehensive review of the movements to targets projected onto the palm or onto the back of a left hand. applications of fNIRS to brain disorders, the findings from the few studies On some trials, the left hand was their own, but on other trials, the left hand that have utilized fNIRS to investigate neurocognitive processes associated was a realistic replica. Targets were presented visually only and had no tactile with neurological (Alzheimer’s Disease, Parkinsons’ Disease, epilepsy, dimension. We found that subjects pointed more accurately to targets traumatic brain injury) and psychiatric disorders (schizophrenia, mood presented on the palm of the real hand than to targets presented on the back disorders, anxiety disorders) will also be reviewed. The potential for fNIRS on the real hand, but that there was no such difference for the fake hand. We to provide more ecologically-valid indices of brain function during these also found that pointing to the real hand was more accurate than pointing to investigations will be highlighted throughout. the fake hand. The greater accuracy of pointing movements to targets presented on the real hand compared to the fake hand is consistent with reports of enhanced visual processing of stimuli presented near the body. 429 B301 This advantage may be due to bimodal cell recruitment by visual stimuli near SPATIOTEMPORAL INVESTIGATION OF HIPPOCAMPAL the hand. Also, the higher accuracy of pointing movements to targets on the ELECTRICAL ACTIVITY USING ADAPTIVE FILTERS palm of the subject’s real hand relative to on the back of their hand may Marija Cotic, Miron Derchansky, Peter L. Carlen, Berj L. Bardakjian. reflect greater bimodal cell representation of areas of the body with higher 1Institute of Biomaterials and Biomedical Engineering, University of tactile receptor density. Toronto, Toronto; 2Department of Physiology, University of Toronto, Toronto; 3Toronto Western Research Institute, Toronto; 4Department of Electrical and Computer Engineering, University of Toronto, Toronto 427 D147 FAILURE TO COMPENSATE FOR LIMB MECHANICS IN A large area of research is currently focused on the development of signal PROPRIOCEPTIVELY-GUIDED SACCADES processing tools able to quantify the level of association, synchrony and/or L Ren and DJ Crawford. 1. Centre for Vision Research, York University; 2. commonality within and between different regions of the brain, as the Canadian Institutes Group for Action and Perception initiation, maintenance and spread of electrical activity in the brain is still not well understood. Traditional tools have provided effective analysis options, Does the saccade generator have a complete internal model of limb but are constrained by limitations, such as stationarity conditions, time- mechanics? In our previous paper (Ren et al. 2006), anisotropic errors were frequency resolution and the inability to identify non-concurrent

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commonalities arising from shifts or delays in signal conduction. We are 431 B304 proposing the application of adaptive filters for tracking of spatiotemporal TRANSPLANTATION OF BONE MARROW DERIVED commonalities of electrical activity in the brain. Adaptive filters are MESENCHYMAL STROMAL CELLS AS A SCAFFOLD FOR advantageous in system identification, as they are able to self-adjust their ADULT NEURAL STEM/PROGENITOR CELLS IN THE INJURED frequency response with time, as a function of the input signal. We use an ADULT RAT SPINAL CORD adaptive filter model with the least mean square (LMS) optimization Parr AM*, Kulbatski I, Zahir T, Wang X, Keating A, and Tator CH. Toronto algorithm, to track the changes of the frequency response of the system. Here Western Hospital, Princess Margaret Hospital, University of Toronto we have implemented our adaptive filter model to characterize the short term changes from four simultaneous extracellular field recordings in the CA1 Transplantation of adult rat neural stem/progenitor cells (NSPCs) into the region of the intact mouse hippocampus under control conditions and in a injured spinal cord results in neural differentiation but poor survival. In low-Mg2+ epilepsy model. The adaptive filter system provided the input- contrast, bone marrow derived mesenchymal stromal cells (BMSCs) survive output response of our model temporally, across individual channels, and well, but do not differentiate into cells of neural lineage. The purpose of these spatiotemporally, between neighbouring recording sites. The development of experiments was to examine the survival and fate of NSPCs after effective signal processing tools-which aid in characterizing the transplantation into the injured adult rat spinal cord 9 days after spatiotemporal spread of electrical activity in the brain-would lead to a transplantation of a BMSC scaffold. Functional neurological recovery was deeper understanding of cellular and network function during normal and also examined at 12 weeks. BMSCs were cultured from adult male rats and pathological neuronal processes. transplanted immediately after clip compression injury (27g force). NSPCs were cultured from either the brain or the spinal cord of rats expressing enhanced green fluorescent protein (eGFP) and transplanted 9 days later. 430 B303 Controls included transplantation of BMSCs only, NSPCs only, and culture AN INJECTABLE DRUG DELIVERY SYSTEM FOR medium. Rats were sacrificed at 12 weeks after NSPC transplantation. THERAPEUTIC AGENTS TO THE INJURED SPINAL CORD Immunohistochemistry was used to identify cell survival and fate. Functional Catherine Kang (1,2), Peter Poon (1), Charles Tator (3), Molly Shoichet neurological recovery was also studied with weekly locomotor and (1,2). (1) Department of Chemical Engineering and Applied Chemistry, (2) ladderwalk testing over a 12 week period. A significant functional recovery Institute for Biomaterials and Biomedical Engineering, (3) Toronto Western was seen in rats receiving spinal cord derived NSPCs only. Rats receiving Research Institute; University of Toronto either BMSCs alone, or both BMSCs and NSPCs did not show functional recovery. Cell survival of BMSCs was better than NSPCs in all groups, and After the initial impact of a traumatic spinal cord injury (SCI), a transplantation of the BMSC scaffold did not affect either the survival or fate secondary injury occurs that leads to further tissue degeneration and greater of the NSPCs. BMSCs did not differentiate into cells of neural lineage and neurological deficit. Current drug administration for this condition is limited produced a large amount of collagen. NSPCs differentiated mainly into by the inability of drugs to cross the blood-spinal cord barrier (BSCB), as astrocytes and oligodendrocytes, and were seen in association with both well as side affects from high dosage required to reach the site of injury. We axons and myelin. Transplantation of adult rat spinal cord derived NSPCs can have developed a biopolymer blend of hyaluronan and methylcellulose provide a significant functional improvement in a 27g clip model of spinal (HAMC) as an injectable drug delivery system that can be administered in cord injury. The strategy of BMSC transplantation to provide a biological the intrathecal space at the level of SCI. Previous work with this material scaffold for the BMSCs did not result in a functional improvement, and the shows that it is safe for in vivo use, and further work is currently being BMSC scaffold attenuated the functional recovery seen with NSPCs alone. performed to characterize material degradation, drug release, and in vivo This may be the result of the large amount of collagen produced which may utilization of this as a drug delivery system (DDS). The degradation contribute to the scar at the site of injury. properties of the HAMC material were investigated with Spraque Dawley rats. Prior to injection, HA was labelled with Flourescein and MC with Texas Red. After a laminectomy at T1-2, the HAMC blend was injected into the 432 B305 intrathecal space. Tissue was harvested over 5 days, frozen and cut into 2mm FNIRS MEASUREMENT OF CEREBRAL BLOOD FLOW IN A longitudinal sections. Analysis suggests that HA degrades faster than MC in SUBJECT WITH UNILATERAL LESION OF THE LEFT FRONTAL the intrathecal space, and MC is visible for up to 3 days after injection. To LOBE investigate the efficacy of HAMC as a DDS a model protein, erythropoietin Anthony C. Ruocco, Anna C. Merzagora, Sarah L. Allen, Maria T. Schultheis, (EPO), was chosen due to its potential as a neuroprotective drug. An in vitro Lori-Ann Tuscan, Tiffany Lake, Farzin Irani, Banu Onaral, & Douglas L. ELISA assay was used to determine the temporal release profile of EPO from Chute. Department of Psychology, Neuropsychology Program, Drexel HAMC. Results showed sustained release of EPO from HAMC occured over University, and School of Biomedical Engineering, Science, & Health a 16hr period. A TF-1 cell line responsive to EPO was used to ensure that Systems, Drexel University bioactivity was maintained after release from HAMC. Following this characterization, an in vivo study has been performed to investigate the Functional near infrared spectroscopy (fNIRS) is an emerging brain efficacy of EPO delivered with HAMC into the intrathecal space. Following imaging technology that permits 24/7 ambulatory non-invasive monitoring a 35g clip injury at T1-2, one of four injections was performed: 1) intrathecal of functional cerebral blood flow during the performance of motor and injection of HAMC, 2) intrathecal injection of HAMC containing EPO, 3) cognitive tasks. fNIRS measures relative changes in oxygenated (oxy-Hb) intrathecal injection of EPO, or 4) intraperitoneal injection of EPO. and deoxygenated (deoxy-Hb) hemoglobin using infrared light that is Behavioural analysis with BBB and grid walking was performed over 6 differentially absorbed by biological tissues in the range of 700-1000 nm. weeks, and subsequently tissue was harvested. Immunohistochemistry was While some studies have inspected the validity of fNIRS by comparing its performed on frozen, sectioned tissue to investigate inflammation, cavity signals with the blood-oxygen level dependent signal of fMRI, no volume, and neural sparing. Results suggest that EPO is capable of crossing investigation has examined the validity of fNIRS as it relates to measurement the BSCB, and there was limited benefit for local delivery of EPO to the of hemodynamic activity in lesioned cortical regions. The aim of the present injured spinal cord. study is to examine functional cerebral blood flow using fNIRS in a 59-year old right-handed subject with a discrete evacuated subdural hematoma in the dorsolateral region of the left frontal lobe extending to insula and left temporal pole. The 18 cm ? 6 cm ? 0.8 cm probe consisting of four light sources surrounded by 10 photo-detectors was placed in two separate

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positions during testing. The first position was over standard EEG 434 B307 placements F7, Fp1, Fp2, and F8, and the second position was just anterior BIOENGINEERING BRAIN-DERIVED STEM CELL-COATED to placements C3, Cz, and C4. Testing was repeated after 21 days. During TUBES FOR SPINAL CORD INJURY REPAIR scanning, the subject completed three tasks: Valsalva maneuver, verbal Tasneem Zahir (1,3), Hiroshi Nomura (2), Guo XiaoDong (2), Howard Kim (phonemic) fluency, and right- and left-hand finger tapping. The verbal (1), Charles Tator (2), Cindi Morshead (1,4), Molly Shoichet (1,3). (1) fluency task resulted in significant increases in oxy-Hb relative to rest in the Terrence Donnelly Centre for Cellular & Biomolecular Research, (2) Toronto spared left medial area of the prefrontal cortex (Brodmann’s area 9). Finger Western Research Institute, (3) Department of Chemical Engineering & tapping with the right hand activated more voxels in the ipsilateral premotor Applied Chemistry, (4) Department of Surgery, University of Toronto area than in homologous but lesioned contralateral cortical regions. The results suggest that fNIRS provides valid measurements of hemodynamic We are currently developing bioengineered, brain-derived stem cell activity in cortical areas associated with generation of words and sequential (BSC)-coated tubes for implantation into the injured spinal cord. This finger tapping. In line with expectations of attenuated signal in lesioned involves an entubulation strategy for regeneration after injury to the spinal cortical regions, fewer voxels were activated in lesioned areas of the left cord based on a combination therapy that includes BSCs, biodegradable frontal lobe during simple motor movements. Overall, the findings provide chitosan tubes and drug delivery systems (DDS). BSCs used in this study preliminary support for the validity of fNIRS as a measure of hemodynamic were isolated from the subependymal region of the forebrains of adult EGFP activity for structurally intact regions of the cortex. transgenic rats. These BSCs were seeded into the inner lumen of chitosan tubes to generate uniform multicellular layers lining the inner tube wall. The neurosphere tubes were then implanted into the rat spinal cord transection 433 B306 site at T8 to determine cell survival and differentiation in vivo. Results of the PREDICTORS OF HEAD COMPUTED TOMOGRAPHY USE FOR 5 week in vivo study showed excellent cell survival of BSCs, as well as PATIENTS WITH MILD TRAUMATIC BRAIN INJURY IN THE differentiation into primarily astrocytes and oligodendrocytes. In addition, in PRIMARY CARE SETTING vitro differentiation studies were carried out in which BSCs were treated with Won Hyung A. Ryu*1,2 Hon BSc., MSc Candidate; Dr. Anthony Feinstein2,3 several reagents including BMP-2, CNTF, dbcAMP, and PDGF-AA for 7 MPhil., PhD., FRCPC; Dr. Angela Colantonio2,4 Ph.D., M.H.Sc., days, in the absence of mitogens. The effects of different treatments were B.Sc.(O.T.); Dr. David L. Streiner,1,2 PhD., C. Psych.; Dr. Deirdre determined on the basis of changes in cellular morphology and appropriate Dawson1,2 PhD. ,MSc., OT Reg. Baycrest Centre1; University of Toronto2; marker expression (Beta 111-tubulin for neurons, GFAP for astrocytes, RIP Sunnybrook Health Sciences Centre3; Toronto Rehab Institute4 for oligodendrocytes). Results obtained from the in vitro screening of exogenous factors for their differentiation potential on BSCs, will inform our OBJECTIVE: To determine which patient characteristics predict the use choice of the appropriate factor for incorporation into the DDS being of head CT for mild traumatic brain injury (TBI) in the primary care setting. developed in our laboratory. These tissue-engineered DDS tubes will be DESIGN: Retrospective study. SETTING: Emergency Departments (ED) implanted in vivo to determine their ability to promote axonal regeneration around Ontario, Canada. METHOD: 855 cases of potential mild TBI were after traumatic injury to the spinal cord. collected from 3 months of health records provided by 9 participating EDs. Pearson Chi-squared test for nominal data and Student’s unpaired two-tailed t test for continuous data were used to determine the univariate association of patient characteristics with use of head CT. Logistic regression with conditional forward stepwise selection analysis was used to identify significant patient characteristics (independent variables) associated with the use of brain radiography (dependent variable). RESULTS: It was found that geographical location of the hospitals (urban vs. rural), arrival mode, presence of Loss-of-Consciousness (LOC) or Post-Traumatic Amnesia (PTA), and nausea were significant predictors of brain radiography use in the primary care setting for mild TBI. CONCLUSION: The results support our hypothesis that geographical location does indeed affect whether a patient with mild TBI receives head CT or not. Furthermore, the findings highlight the variability in current diagnostic procedures. Additional analyses will be performed to determine if variability exists between trauma vs. non-trauma centers and teaching vs. non-teaching hospitals. The results will aid in determining feasible recommendations to improve the knowledge of clinicians in all regions of Ontario regarding early detection and assessment of mild TBI. Key words: Traumatic Brain Injury, Head Imaging, Primary care.

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THANK YOU FROM THE CANADIAN ASSOCIATION FOR NEUROSCIENCE!

THE PUBLICATION OF THIS ABSTRACT BOOK WAS MADE POSSIBLE

THROUGH THE GENEROSITY OF:

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INDEX

Aarts, Michelle ...... 226A201 246A221 339D221 Beazely, Michael ...... 293C204 Abi Farah, Carole ...... 227A202 239A214 Beck-Sickinger, Annette G...... 244A219 Abou Ezzi, Samer ...... 113A101 Bedard, Marc-Andre ...... 405D126 417D137 Adamchik, Yana ...... 314C225 Bell, Andrew ...... 3B103 Adamec, R...... 212D415 Belleville, K...... 392A141 176C132 Afolabi, Ezekiel ...... 228A203 Belmare, M.P...... 246A221 Ahuja, Tarun ...... 229A204 Benatar, A...... 41C116 Aiga, M...... 324D206 Beninger, Richard J...... 4B104 193C149 Aigaki, Toshiro ...... 82B408 Berg, David ...... 382A131 Alier, Kwai A...... 320D202 Berg, Eric A...... 93B419 Alim, Ishraq ...... 230A206 Bergado, J...... 49C124 Allen, Craig ...... 115A103 56D106 Bernier, Louis-Philippe ...... 315C226 Allen, Sarah L...... 432B305 Berube, Patrick ...... 143B126 Almasieh, Mohammadali ...... 116A104 Bérubé-Carrière, Noémie ...... 237A212 Almazan, Guillermina ...... 90B416 77B403 Beuk, Jonathan ...... 4B104 Alves, Nyresa ...... 70D120 Bian, Liu ...... 121A109 Amah, L.O...... 228A203 Bibollet-Bahena, Olivia ...... 77B403 Anderson, Adam ...... 14B114 Bienenstock, J...... 366C306 Ando, D...... 155B138 Biernaskie, Jeff ...... 78B404 186C142 Andrew, R David ...... 231A206 Black, S...... 29C104 Anisman, H...... 170C126 Black, S.E...... 52D102 Antony, Joseph ...... 75B401 Blais, Dominique ...... 315C226 Apte, Sameer ...... 413D133 Blanchet, Pierre J...... 405D126 417D137 Araki, Toshiyuki ...... 88B414 Bland, Brian H...... 269B212 205D408 Arbour, N...... 97C404 Blinder, S...... 122A110 406D127 Armstrong, Gary ...... 232A207 Boehnke, Susan ...... 382A131 Arnott, Stephen ...... 1B101 388A137 Boggs, Joan M...... 238A213 306C217 Arundine, M...... 282B225 Bogusz, Elliott ...... 122A110 406D127 Ase, Ariel ...... 233A208 Bomont, Pascale ...... 213D416 Atwood, Harold L...... 249A224 274B217 268B211 Boon, F...... 183C139 191C147 Aubert, Isabelle ...... 234A209 242A217 Boon, Y...... 161B144 Avramescu, Sinziana ...... 117A105 Borie, Denis ...... 124A112 Bachraoui, Ikram ...... 370C310 Bosch, Daniel ...... 383A132 70D120 Badeaux, F...... 99C406 Bosnyak, Dan ...... 384A133 18B118 Bagot, Rosemary ...... 68D118 Bougie, Joanna ...... 239A214 Baillargeon, Joanie ...... 235A210 Bourget-Coulombe, Sabrina ...... 124A112 Baimoukhametova, Dina ...... 261B204 Bourque, Charles W...... 345D227 Bains, Jaideep S. 220D304 236A211 261B204 278B221 298C209 Bourque, Marie-Josee ...... 301C212 Bakke, D.P...... 20B120 Bousquet, Mélanie ...... 123A111 Baldi, Pierre ...... 382A131 Bouvier, David ...... 240A215 Balena, Trevor ...... 336D218 Bowie, Derek 257A232 ...... 100C407 334D216 Balodis, Iris ...... 2B102 Boyd, A...... 89B415 Bamji, S.X...... 324D206 Bracken, Michael B...... 138A126 Bamji, Shemaz X...... 327D209 Brice, Alexis ...... 233A208 Bandaru, Sirisha ...... 93B419 Brebner, K...... 266B209 Barakat, Meredith ...... 137A125 Brennan, Jordan ...... 111C418 0 Bardakjian, Berj L...... 429B301 Brewster, Paul ...... 72D122 Barker, Philip A...... 371A401 Bronskill, M...... 29C104 Barnett-Cowan, Michael ...... 118A106 Brooks, Patricia ...... 241A216 Barr, C.L...... 159B142 Brotchie, J.M...... 178C134 Barrett, Curtis F...... 332D214 Broussard, D.M...... 400A149 416D136 Bartkowska, K...... 101C408 Brown, Zenya ...... 5B105 Basiri, Mohsen ...... 119A107 Brown, Leslie ...... 277B220 Bastianetto, Stephane ...... 120A108 Brown, Liana E...... 426D146 Bastien-Dionne, Pierre-Olivier ...... 76B402 Brown, Mary ...... 154B137 Bean, Jim ...... 14B114 Brudzynski, Stefan ...... 385A134 10B110 Beaudet, N...... 392A141 176C132 424D144 Brunette, E...... 189C145 Beaudry, Helene ...... 140A128 Bucarelli, D...... 18B118

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Buck, B...... 29C104 Comas, Tanya ...... 245A220 Budell, Lesley ...... 386A135 Constantin, A.G...... 390A139 Buist, R...... 374A404 Cook, Erik P...... 413D133 Bunce, Scott ...... 428B302 Coolen, Lique M...... 352A302 354A304 391A140 Burgdorf, Jeff ...... 10B110 Coorssen, Jens ...... 289B232 Burgdorf, Jeffrey ...... 48C123 Cordeau, Pierre ...... 128A116 Burgess, Alison ...... 242A217 234A209 Cordes, Sabine ...... 81B407 Burgess, Christian ...... 387A136 Corera, Amadou T...... 233A208 296C207 Burke, Mark ...... 124A112 Corera, Tidjane A...... 240A215 Busch, Sarah ...... 112C419 Corneil, Brian ...... 394A143 Cabana, Therese ...... 79B405 Cotic, Marija ...... 429B301 Cahill, C.M...... 145B128 Counotte, Danielle ...... 354A304 Cain, D.P...... 161B144 183C139 191C147 Courtemanche, Richard ...... 405D126 Calon, Frédéric ...... 123A111 210D413 Crawford, J. Douglas . .394A143 390A139 28C103 38C113 44C119 Campos, Ana R...... 268B211 Crawford, J. Douglas ...... 427D147 67D117 419D139 Cant, Jonathan ...... 388A137 1B101 Cregan, Sean ...... 214D417 Cantor, A...... 180C136 Cui, Hong ...... 246A221 188C144 Carlen, Peter L...... 150B133 429B301 307C218 Cui, Wen ...... 247A222 Carlen, Peter L...... 314C225 182C138 203D406 Culham, Jody C...... 17B117 418D138 67D117 Carmichael, Brendan ...... 125A113 Cull, Amanda ...... 303C214 Carmichael, Nicole ...... 126A114 Cummins, Erin ...... 125A113 33C108 Castonguay-Lebel, Z...... 349D231 Cyr, Michel ...... 329D211 Cavina Pratesi, Cristiana ...... 17B117 Da Silva, Felipe ...... 225A401 Chabot-Dore, Anne-Julie ...... 315C226 Dal Bo, G...... 237A212 Chagnon, Miguel ...... 240A215 Danik, Marc ...... 267B210 Chakrabartty, Avijit ...... 154B137 Dansereau, Marc-André ...... 248A223 392A141 176C132 Chakravarthy, Balu ...... 277B220 Darby-King, Andrea ...... 247A222 Chambers, Adam ...... 351A301 Dasilva, Kevin ...... 154B137 Chan, Allen ...... 243A218 Dason, Jeffrey ...... 249A224 Chan, Richard ...... 88B414 David, Samuel ...... 141A129 173C129 Chapman, Craig ...... 389A138 Dawson, Deirdre ...... 433B306 Charlton, Milton P...... 319D201 De Koninck, P...... 292C203 Charron, Frederic ...... 95C402 De Koninck, Yves ...... 310C221 Chatalov, Vitali ...... 127A115 De Luca, Vincenzo ...... 129A117 185C141 Chauvette, Sylvain ...... 6B106 de Oliveira, Cleusa ...... 354A304 391A140 Chee, Melissa ...... 244A219 de Souza, R...... 135A123 Chen, Bin ...... 184C140 deCatanzaro, Denys ...... 211D414 Chen, R...... 130A118 Deemyad, Tara ...... 212D415 0 Chen, Simon ...... 144B127 Delaney, Kerry ...... 250A225 Chen, X...... 212D415 DeMill, Colin ...... 82B408 Chen, Y.Y...... 343D225 Denis, D.J...... 424D144 Cheng, Guanliang ...... 352A302 Dequen, Florence ...... 213D416 0 Cheng, ...... 102C409 Derchansky, Miron ...... 429B301 307C218 Cheng, C...... 343D225 Desbiolles, Caroline ...... 356A306 Cheung, E...... 97C404 Descalzi, Giannina ...... 130A118 Cheung, Eric C.C...... 146B129 Descarries, Laurent ...... 251A226 Cheung, Herman H...... 217D301 Descarries, Laurent ...... 378A408 237A212 280B223 Chiang, Cindy ...... 48C123 DesGroseillers, Luc ...... 286B229 99C406 Choe, Yuri ...... 345D227 0 Dhir, Sabine ...... 355A305 Chojnacki, Andrew ...... 80B406 Di Polo, Adriana ...... 116A104 287B230 Chou, C. Jennifer ...... 268B211 Dickson, Clayton ...... 9B109 Chouinard, Philippe ...... 7B107 Diec, Diana ...... 83B409 Chouinard, Sylvain ...... 153B136 168B151 Dinelle, K ...... 122A110 406D127 Christie, B.R...... 266B209 Dion, P...... 181C137 Chung, J-Y. J...... 416D136 Djazayeri, Shabdis ...... 115A103 Chute, Douglas L...... 225A401 428B302 432B305 Djedovic, Alex ...... 70D120 0 Cicchetti, Francesca...... 132A120 142A130 123A111 177C133 Djerroud, Nadera ...... 168B151 Cisse, Youssouf ...... 163B146 Domianidze, T...... 32C107 Clark, Julie ...... 303C214 Doré-Savard, Louis ...... 392A141 Clement, Elizabeth A...... 9B109 Dorris, Michael ...... 27C102 37C112 58D108 Colantonio, Angela ...... 433B306 Dostrovsky, J.O...... 272B215 201D404 411D131 404D125 Colbourne, F...... 374A404 Doucet, Guy ...... 240A215 330D212 Cole, C.J...... 110C417 Doucette, J. Ronald ...... 108C415 Colmers, William F...... 353A303 244A219 295C206 Doucette, R...... 119A107 Colwell, Keri L...... 158B141 Doyle, Krissy ...... 131A119

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Drapeau, Pierre ...... 148B131 Fragoso, G...... 90B416 Drew, T...... 423D143 Francis, Beverly ...... 137A125 Drolet, Guy ...... 358A308 25B125 349D231 Francis, B...... 152B135 Drouin-Ouellet, Janelle ...... 132A120 Frankland, Paul W...... 15B115 196C152 110C417 D'Souza, Cheryl ...... 84B410 202D405 Fraser, Paul ...... 202D405 Du, L...... 170C126 Fredin, K.N...... 311C222 Duffin, J...... 379A409 Freeman, T...... 177C133 Duffus, Shannon ...... 10B110 Friebel, Kirstin ...... 244A219 Durocher, Yves ...... 371A401 Fry, Mark ...... 256A231 Dvorak, R...... 276B219 Fudge, Melissa ...... 16B116 Dyck, Richard H...... 162B145 Fuerth, Ben ...... 214D417 0 Dyde, R.T...... 118A106 Furey, Matt ...... 112C419 Dykstra, Crystal ...... 133A121 Furlan, Julio ...... 138A126 Echeverry, Stefania ...... 85B411 Furstoss, Olivia ...... 88B414 Edmundson, C...... 374A404 Gagne, Anne-Marie ...... 300C211 Eftekharpour, Eftekhar ...... 86B412 Gahwiler, B.H...... 299C210 Eikelboom, Roelof ...... 11B111 Galan, Alba ...... 257A232 100C407 El Beheiry, Hossam ...... 86B412 Gallivan, Jason ...... 17B117 Elbejjani, Martine ...... 356A306 Gander, Phillip ...... 18B118 Elia, A.J...... 149B132 Gander, P.E...... 384A133 Elsohemy, Amal ...... 393A142 Gandhi, Anusha ...... 139A127 Emrich, Stephen ...... 12B112 Gao, Mary X...... 197C153 Engbers, Jordan D...... 298C209 Gao, Wen ...... 306C217 Erb, S...... 5B105 31C106 Garcia, A...... 166B149 Ervin, Frank R...... 356A306 124A112 Garcia, Kristine ...... 215D418 0 Estupinan Diaz, Barbara ...... 134A122 Gardam, Kate ...... 258B201 Eubanks, James ...... 307C218 217D301 Garman, D...... 246A221 Everdell, Ian ...... 13B113 Gauthier, Andree ...... 88B414 Everling, S...... 43C118 63D113 Gauthier, A.S...... 101C408 Fahlings, Michael G...... 138A126 Ge, Y...... 266B209 Fahnestock, Margaret . . . . . 194C150 215D418 219D303 220D304 Geiger, Julia ...... 259B202 Fallon, Lara ...... 233A208 Geis, Hans-Ruediger ...... 51D101 Faludi, G...... 170C126 Gendron, Louis ...... 140A128 Farb, Norman ...... 14B114 Georgescu, M...... 362C302 Farounbi, B...... 164B147 Ghasemlou, Nader ...... 141A129 Farrow, K...... 400A149 Gheidi, Ali ...... 11B111 Farshadmanesh, Farshad ...... 394A143 Ghods-Sharifi, Sarvin ...... 19B119 Fatima, Zainab ...... 14B114 Gibrat, Claire ...... 142A130 Favell, Kristy ...... 371A401 Gilbert, F...... 25B125 Feeney, C.J...... 150B133 Gillis, Jesse ...... 260B203 Fehlings, Michael G...... 86B412 155B138 331D213 207D410 Gingerich, Sarah ...... 357A307 Fei, Guanghe ...... 252A227 262B205 92B418 Girard, N...... 181C137 Feinstein, Anthony ...... 433B306 Goldberg, Jeremy ...... 131A119 Feldcamp, Laura ...... 135A123 Goldberg, Steven R...... 71D121 Fendt, Markus ...... 160B143 Golde, Todd E...... 188C144 Feng, Z.P...... 288B231 Gomez, L...... 159B142 Feng, Zhong-Ping ...... 252A227 262B205 92B418 317C228 Gong, Yuewen ...... 209D412 Ferecsko, Alex ...... 253A228 Goodale, Melvyn A. Ferguson, A.V...... 230A206 367C307 ...... 388A137 389A138 1B101 7B107 65D115 426D146 Ferguson, Alastair V...... 256A231 360A310 Goodman, Robert L...... 352A302 Ferraro, Gino ...... 239A214 Gordon, Grant 261B204 ...... 298C209 Ferrus, A...... 249A224 Gordon, Tessa 112C419 ...... 216D419 Fiserova, A...... 276B219 346D228 Gore, Joanna ...... 395A144 Floresco, S.B...... 19B119 55D105 64D114 Gosselin, R.D...... 248A223 Foerster, Anne ...... 87B413 Gosselin-Kessiby, Nadia ...... 396A145 Fon, Edward A...... 233A208 240A215 296C207 Gould, P...... 177C133 Fong, Jamie ...... 254A229 Gowing, Genevieve ...... 213D416 Ford, Christopher ...... 255A230 Gowing, M...... 281B224 Forder, Joan ...... 136A124 226A201 136A124 188C144 Gozdzik, Marta ...... 421D141 Foster, Jane A...... 366C306 211D414 Graham, M.D...... 362C302 Fouad, Karim ...... 112C419 Gravel, Claude ...... 321D203 Fournier, Alyson ...... 371A401 Gray, Jack ...... 20B120 Fox, C.J...... 266B209 Green, Andrea ...... 397A146 Fradin, Cecile ...... 323D205 Greenberg, Mike E...... 106C413 Fraenkl, Stephan ...... 137A125 Grieder, Taryn ...... 21B121

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Grignon, Sylvain ...... 143B126 Howland, John ...... 266B209 Gritsenko, Valeriya ...... 398A147 Hoyda, Ted ...... 360A310 Gros-Louis, Francois ...... 148B131 Hryciw, E.L...... 311C222 Guest, B.B...... 20B120 Hu, Bin ...... 205D408 Guillemette, A...... 392A141 Huang, M...... 340D222 Guizard, N...... 46C121 Huang, X...... 322D204 Guo, C...... 288B231 Huh, Carey You Lim ...... 267B210 Guo, Conghui ...... 262B205 Hui, Kelvin ...... 91B417 Gupta, Saurabh ...... 137A125 Hui, Kwokyin ...... 92B418 Gurd, James W...... 133A121 217D301 Hutchison, W.D...... 404D125 411D131 201D404 Haagaard, Alexandra ...... 271B214 Huynh, Michael L...... 81B407 Haas, Kurt ...... 144B127 Idrsi, S...... 164B147 Haber, Michael 263B206 ...... 341D223 Inoue, Wataru ...... 361C301 368C308 Hader, Walter ...... 80B406 Irani, Farzin ...... 428B302 432B305 Hadj-Bouziane, Fadila ...... 3B103 Iremonger, Karl J...... 236A211 Hal, Geoffrey ...... 211D414 Ismail, Nafissa ...... 362C302 Hall, Amee J...... 425D145 Itti, Laurent ...... 382A131 Hall, Geoffrey ...... 131A119 Iyengar, Balaji ...... 268B211 Haluk, Desirae M...... 64D114 Jackson, Jesse ...... 269B212 205D408 Han, C...... 340D222 Jackson, Michael ...... 270B213 Han, Thida ...... 65D115 Jackson, J...... 183C139 Hanif, Asad ...... 223D307 Jackson, P.L...... 386A135 Hao, Z...... 149B132 Jadavji, Nafisa ...... 401A150 158B141 Harauz, George ...... 306C217 Jaglal, S...... 373A403 Harley, Carolyn W...... 247A222 Jahani-Asl, Arezu ...... 146B129 Harrar, Vanessa ...... 22B122 Jalini, Shirin ...... 203D406 Harris, L.R...... 118A106 Jansen, Karen ...... 188C144 Harris, Laurence R...... 39C114 Jeong, S.Y...... 173C129 Harrison, Sarah ...... 23B123 Jeyaraju, Danny ...... 93B419 Harrison, A...... 66D116 Jhamandas, K...... 145B128 Hassanzadeh, Gholamreza ...... 381A411 0 Joch, Monica ...... 233A208 Havrdova, E...... 276B219 346D228 Johnsrude, Ingrid S...... 2B102 Hayashi, A...... 246A221 Johnston, K...... 43C118 63D113 Hayley, S.P...... 111C418 Jones, Michael ...... 147B130 Hayley, Shawn ...... 139A127 375A405 Jones, Sherri ...... 363C303 Hegedus, J...... 216D419 Jones, Emma V...... 341D223 Hemraj, A...... 166B149 Jones, M...... 282B225 Henderson, Jeffrey T...... 89B415 91B417 149B132 Jones, Michael ...... 188C144 Henkelman, R.M...... 89B415 Jones, S.L...... 362C302 Henriques, Denise Y.P. Joseph, J...... 133A121 ...... 61D111 410D130 414D134 415D135 419D139 422D142 Josselyn, Sheena ...... 204D407 Henry, Melaine ...... 358A308 Josseolyn, S.A...... 110C417 Herter, Troy ...... 399A148 Joy, J...... 133A121 Heskin-Sweezie, Raquel ...... 400A149 416D136 Jugloff, Denis G.M...... 217D301 Hewapathirane, D. Sesath ...... 144B127 Julien, Carl ...... 123A111 210D413 Hewitt, M...... 189C145 Julien, Jean-Pierre ...... 113A101 167B150 213D416 Hideg, Christopher ...... 422D142 Jung, Benjamin ...... 217D301 0 Hince, P...... 181C137 Kabashi, Edor ...... 148B131 Hinds, Andrea ...... 24B124 Kaifosh, Patrick ...... 271B214 Hines, Dustin J...... 264B207 325D207 Kalaska, J.F...... 396A145 397A146 398A147 Hirasawa, Michiru ...... 359A309 Kalisch, Bettina ...... 333D215 Ho, Stephanie ...... 89B415 Kam, A...... 102C409 Ho, Warren ...... 217D301 Kamibayashi, Kiyotaka ...... 402A151 Hodaie, M...... 130A118 201D404 404D125 411D131 Kan, Janis ...... 27C102 Hodler, Céline ...... 25B125 Kane, Abdoul ...... 272B215 Hoffman, J.E...... 161B144 Kaneuchi, Taro ...... 82B408 Hoffmann, Ewa ...... 208D411 Kang, Catherine ...... 430B303 Holdridge, Sarah ...... 145B128 Kania, Artur ...... 95C402 Holmes, M.J...... 87B413 Kanungo, Anish ...... 149B132 Hong, Elizabeth J...... 106C413 Kaplan, D.R...... 101C408 109C416 110C417 Hoover, Adria ...... 26C101 Kaplan, David R...... 88B414 106C413 Hopman, Romina ...... 265B208 Karajgikar, Meera ...... 214D417 Horne, Patrick ...... 154B137 221D305 Karimi-Abdolrezaee, Soheila ...... 86B412 Hoshooley, Jennifer S...... 73D123 Kassardjian, C.D...... 416D136 Hossain, Shireen ...... 90B416 Kavaliers, F...... 191C147

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Kavaliers, Martin ...... 16B116 161B144 74D124 Lake, Tiffany ...... 432B305 Kavousi, Borna ...... 150B133 Lalancette-Hébert, Mélanie ...... 281B224 Kawashima, Noritaka ...... 402A151 408D128 Lamoureaux, ...... 79B405 Keating, A...... 431B304 Langel, Ülo ...... 320D202 Keith, Gerald ...... 28C103 Langman, T...... 152B135 Keller, A.Florence ...... 151B134 Laroughe, Annie ...... 143B126 Kelly, John ...... 80B406 Lau, Anthony ...... 282B225 147B130 Kennedy, J.L...... 135A123 159B142 185C141 Laurent, Charles E...... 286B229 Kennedy, James L...... 129A117 Lavallee, A...... 79B405 Kerr, B...... 173C129 Lavoie, Nathalie ...... 283B226 284B227 Khananashvili, M...... 32C107 Law, Peggy ...... 329D211 Khangura, Jaspreet ...... 278B221 Le Bel, Manon ...... 329D211 Kideckel, David ...... 29C104 Le Foll, Bernard ...... 71D121 0 Kigar, D.L...... 29C104 52D102 Lebeau, Genevieve ...... 286B229 Kim, Howard ...... 94C401 LeBel, E...... 292C203 Kim, John ...... 152B135 Lebrun-Julien, Frederic ...... 287B230 Kim, E...... 404D125 Lee, David ...... 288B231 Kim, Howard ...... 434B307 Lee, G...... 155B138 Kim, John H...... 137A125 LeGrand, Jaclyn ...... 97C404 King, N...... 159B142 Lehman, Michael N...... 352A302 Kirouac, Gilbert ...... 372A402 Lehmann, Amanda ...... 289B232 Kirov, Sergei A...... 231A206 Lehmann, Hugo ...... 290C201 Kirz, J...... 281B224 Lemasson, Morgane ...... 291C202 Kisilevsky, Alexandra ...... 273B216 Lemay, Martin ...... 153B136 168B151 Kiss, E...... 159B142 Lemieux, Mado ...... 292C203 Kitabgi, P...... 248A223 Lemieux, M...... 79B405 Klier, E.m...... 390A139 Leone, A.M...... 384A133 Klose, Markus ...... 274B217 Leri, F...... 40C115 Knogler, L.D...... 250A225 Leri, Francesco . . . .115A103 125A113 33C108 56D106 333D215 Ko, Ji Hyun ...... 30C105 Letellier, Marie-Claude ...... 93B419 Kohler, Stefan, ...... 7B107 Lett, Robyn ...... 98C405 Kontogiannea, Maria ...... 233A208 Lévesque, Maxime ...... 405D126 Kovacs, Krisztina ...... 253A228 275B218 275B218 Levesque, D...... 235A210 132A120 25B125 Kovacs, M...... 159B142 Levesque, Martin ...... 165B148 Kovaru, Frantisek ...... 276B219 Levine, Brian ...... 187C143 Kovaru, F...... 346D228 Levy, Anne Marie ...... 115A103 56D106 Kovaru, H...... 276B219 Li, Peter ...... 175C131 Kovaru, Hana ...... 346D228 0 Li, R.F...... 340D222 Kowara, Renata ...... 277B220 Li, S...... 372A402 Kraemer, Gary W...... 364C304 Li, X...... 308C219 Kramer, Bianca M.R...... 106C413 Lidstone, Sarah ...... 406D127 Krantic, Slavica ...... 206D409 Lidstone, SC ...... 122A110 Krawchuk, Dayana ...... 95C402 Lieberman, J.A...... 185C141 Krieger, N...... 373A403 Light, Peter E...... 244A219 Kristman, Vicki ...... 373A403 Lim, Aeni ...... 293C204 Kriz, Jasna ...... 151B134 Lim, Travis ...... 239A214 Kroger, Helmut ...... 344D226 Limebeer, Cheryl L...... 174C130 Krukoff, Teresa ...... 357A307 Lin, J...... 152B135 Kucera, J...... 91B417 Lisa, V...... 346D228 Kulbatski, Iris ...... 96C403 304C215 431B304 Litteljohn, D...... 111C418 Kupferschmidt, David ...... 31C106 Liu, Hsueh-Ning Shirley ...... 154B137 Kurtzer, Isaac ...... 403A152 412D132 Liu, Yang ...... 155B138 Kuzmiski, Brent ...... 278B221 Liu, J...... 186C142 La Gamma, E...... 156B139 Liu, P.Q...... 340D222 Labadze, La ...... 32C107 Lo, Alto S...... 9B109 Labban, Margaret ...... 279B222 Lomanowska, Anna ...... 364C304 Labelle, J.-P...... 397A146 Lomber, S.G...... 407D148 LaBrie, John D...... 312C223 Lomber, Stephen ...... 425D145 0 Lacaille, Jean-Claude ...... 286B229 328D210 Lopez-Vales, R...... 173C129 Lacoste, Baptiste ...... 280B223 Lovejoy, David A...... 350D232 Laforest, S...... 349D231 Lowe, Germaine ...... 294C205 Lafrance, Mylene ...... 424D144 0 Lozano, A...... 130A118 404D125 201D404 Lafreniere-Roula, Myriam ...... 404D125 Lozano, A.M...... 411D131 Laganiere, J...... 181C137 Lu, Van ...... 295C206 Lai, D...... 387A136 Lu, P.S...... 246A221

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Luheshi, Giamal N...... 294C205 361C301 368C308 Mechighel, P...... 248A223 Luo, QZ ...... 121A109 Medaglia, John ...... 225A401 Luthi, Andreas ...... 299C210 Mehaffey, W. Hamish ...... 298C209 Lynn, B...... 308C219 Mellott, Jeffrey G...... 425D145 407D148 Ma, Weiya ...... 198D401 218D302 Melnick, Igor V...... 353A303 MacDonald, Penny ...... 233A208 296C207 Ménard, Caroline ...... 300C211 MacDonald, John F...... 270B213 293C204 188C144 Menard, Michel ...... 277B220 MacDonald, Suzanne E...... 39C114 Mendez, J Alfredo ...... 301C212 MacFabe, Derrick ...... 156B139 161B144 Merali, Z...... 170C126 MacFabe, D.F...... 183C139 191C147 Mercier, A. Joffre ...... 289B232 MacGillivray, Lindsey ...... 347D229 0 Mercier, A. Joffre ...... 35C110 35C110 303C214 305C216 MacKewn, Jesse ...... 8B108 Merten, Nicole ...... 244A219 MacLean, David ...... 297C208 334D216 Merzagora, Anna C...... 432B305 MacLellan, Crystal ...... 374A404 Messier, J...... 396A145 MacVicar, Brian A. 264B207 273B216 190C146 325D207 342D224 Metz, Gerlinde A. S...... 401A150 158B141 Madec, Kim ...... 209D412 Michalski, Bernadeta ...... 220D304 0 Magoski, N.S...... 258B201 259B202 326D208 Mielke, John G...... 229A204 302C213 Maher-Laporte, Marjolaine ...... 286B229 Miksys, L. Sharon ...... 376A406 208D411 Mainwaring, L...... 373A403 Mikulic, Areh ...... 58D108 Maj, Mary ...... 137A125 Milakovic, Maja ...... 303C214 Mak, T.W...... 149B132 Miller, Linda ...... 99C406 Makriyannis, Alexandros ...... 351A301 Miller, F.D...... 101C408 109C416 110C417 186C142 Malhotra, Shveta ...... 407D148 Miller, Freda D...... 234A209 88B414 75B401 106C413 Mallet, Paul E...... 50C125 Mills, L.R...... 254A229 83B409 271B214 Mamani, Mandy ...... 307C218 Mills, Linda R...... 369C309 Mangano, E.N...... 111C418 Milstein, David ...... 37C112 Mangano, Emily ...... 139A127 375A405 Misener, Virginia ...... 159B142 Manjunath, Varsha ...... 239A214 Misra, Vikram ...... 107C414 Mann, Amandeep ...... 376A406 Mitchell, R...... 250A225 Marchand, S...... 424D144 Mitra-Bayat, Mohammad ...... 381A411 Marino, Robert A...... 395A144 Mo, Gary ...... 315C226 Marsillo, Diana ...... 202D405 Mogil, Jeffrey S...... 179C135 Martin, S...... 183C139 Mohammad Asef, Y...... 191C147 Martinez, J.C...... 390A139 Mohr, Daniela ...... 160B143 Martinez, Sarah J...... 341D223 Molineux, Michael L...... 298C209 Martinez-Trujillo, J.C...... 38C113 Monchi, O...... 46C121 Masani, Kei ...... 408D128 Monchi, Oury ...... 30C105 Masoudi, Raheleh ...... 219D303 0 Monteon, Jachin ...... 38C113 Massicotte, Guy ...... 300C211 Morante-Redolat, Jose ...... 371A401 Massouh, Mireille ...... 157B140 Moreau, France ...... 233A208 Mateos, Jose Maria ...... 299C210 Moro, E...... 130A118 Mathews, Iva ...... 34C109 Morris, Catherine E...... 369C309 Mathews, I.Z...... 36C111 Morrissey, Brendan F...... 7B107 426D146 Matitaishvili, T...... 32C107 Morshead, C.M...... 102C409 May, Holly ...... 35C110 Morshead, Cindi ...... 86B412 434B307 Mayberg, Helen ...... 14B114 Moscovitch, Morris ...... 187C143 Mayerhofer, Andreas ...... 160B143 Mothe, Andrea ...... 304C215 Mazurek, Michael ...... 347D229 Mott, G.N...... 111C418 McAndrews, Mary Pat ...... 187C143 Mottershead, Megan ...... 305C216 McBride, Heidi ...... 93B419 146B129 Mouginot, Didier ...... 358A308 365C305 McCormick, Cheryl ...... 36C111 Mouihate, Abdeslam ...... 377A407 McCormick, C.M...... 34C109 66D116 Mount, Howard T.J...... 137A125 McCullough, Kimberly ...... 409D129 Mount. T.J...... 152B135 McDonald, D...... 343D225 Moyhammad Asef, Yalda ...... 161B144 McIldowie, M...... 178C134 Muir, Katherine ...... 42C117 McKay, Bruce ...... 298C209 Mulligan, S...... 273B216 McKeon, Deborah ...... 14B114 Mulligan, Sean J...... 264B207 McKinney, Rebecca ...... 299C210 Mullin, Caitlin ...... 72D1220 McKinney, R. Anne ...... 257A232 299C210 Munoz, Douglas P...... 395A144 0131166 014962 D112 McLaurin, JoAnne ...... 137A125 154B137 Murai, K.K...... 263B206 McLean, John H...... 247A222 212D415 Murai, Keith ...... 240A215 341D223 Meakin, S.O...... 311C222 Mushynski, W.E...... 90B416 Mealing, Geoffrey A.R...... 229A204 302C213 Musse, Abdiwahab ...... 306C217 Meaney, Michael J...... 355A305 68D118 Mylvaganam, Shanthini ...... 307C218 Mechawar, Naguib ...... 206D409 Nadeau, Louis ...... 365C305

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Nagakura, Ikue ...... 348D230 0 Peltsch, Alicia ...... 166B149 Nagy, James ...... 308C219 Peng, Yan ...... 351A301 Nakashima, Amy ...... 162B145 Pengfei, Chang ...... 394A143 Nakazawa, Kimitaka ...... 402A151 Peralta, Modesto R...... 285B228 Namaka, Mike ...... 209D412 Perehudoff, S. Katrina ...... 158B141 Nankoo, Jean-Francois ...... 39C114 Perez-Tur, Jordi ...... 371A401 Nankova, B...... 156B139 Perova, Tatiana ...... 175C131 Nash, Joanne E...... 127A115 178C134 223D307 Perrot, Rodolphe ...... 167B150 Nazarali, Adil J...... 108C415 Perrot-Sinal, Tara ...... 42C117 Neel, Benjamin G...... 88B414 Petrides, M...... 46C121 Neufeld, Karen-Anne ...... 366C306 Pfaus, J.G...... 362C302 363C303 Neva, Jason ...... 410D130 Pflieger, J.F...... 79B405 Niel, Ullanda ...... 27C102 Phan, Nam ...... 83B409 Niles, L.P...... 104C411 Philibert, Maxime ...... 168B151 Nita, Dragos A...... 117A105 163B146 Phillips, Jessica ...... 43C118 Nobrega, J.N...... 23B123 Phillips, A.G...... 266B209 406D127 Nomura, Hiroshi ...... 434B307 Phivilay, Alix ...... 210D413 O'Connor, T.P...... 98C405 Piggott, M...... 178C134 Ogboi, Johnbull ...... 164B147 Piomelli, Daniele ...... 174C130 Okolie, V...... 228A203 Pittman, Quentin ...... 351A301 278B221 Okpara, G...... 228A203 Placenza, Franca ...... 169B152 Olah, Michelle E...... 270B213 Platek, Steven M...... 428B302 Olmstead, Mary C...... 2B102 193C149 Plemel, J...... 186C142 Olson, C...... 308C219 Podbielski, D...... 57D107 Onaral, Banu ...... 432B305 Pohl, M...... 248A223 Opferman, J.T...... 97C404 Ponka, P...... 173C129 Ormiston, Trevor ...... 306C217 Poole, Stephen ...... 368C308 Ormond, Jake ...... 309C220 348D230 Poon, C...... 374A404 Oschipok, Loren ...... 202D405 Poon, Peter ...... 430B303 Ossenkopp, K.P...... 183C139 191C147 Popovic, Milos R...... 408D128 Ossenkopp, Klaus-Peter . . . . . 16B116 161B144 174C130 74D124 Poulin, Anne-Marie ...... 60D110 Osswald, Ingrid K...... 257A232 100C407 Poulin, Jean-Francois ...... 349D231 0 Ouassat, Mohamed ...... 380A410 Poulter, Michael ...... 170C126 307C218 Ovari, Jelena ...... 40C115 Prescott, Ian ...... 411D131 Owens, Steven ...... 243A218 Prescott, Steven ...... 310C221 Padmanabhan, Vasantha ...... 352A302 Price, Christopher ...... 360A310 367C307 Pakarian, P...... 130A118 Prime, Steven ...... 44C119 Palkovits, M...... 170C126 Pronchuk, Nina ...... 353A303 Palmour, Roberta ...... 124A112 356A306 Proulx, Eliane ...... 45C120 Panksepp, Jaak ...... 10B110 Provost, Jean-Sebastien ...... 46C121 Paolone, Giovanna ...... 41C116 Pruszynski, J. Andrew ...... 412D132 Pape, H.C...... 49C124 Pruszynski, J.A...... 403A152 Paquet, B...... 235A210 25B125 Ptito, Alain ...... 30C105 Paquin, Annie ...... 101C408 Ptito, Maurice ...... 124A112 Pare, Martin ...... 53D103 Putman, C.T...... 216D419 Parent, Martin ...... 378A408 Quinn, T...... 180C136 192C148 Parent, Rémy ...... 165B148 Quirion, Remi . . .179C135 198D401 206D409 340D222 218D302 Parent, A...... 157B140 420D140 Racine, Ronald J...... 265B208 194C150 Parent, Andre ...... 76B402 291C202 165B148 Radojevic, Vesna ...... 171C127 Parent, Carine ...... 355A305 68D118 Rainville, P...... 386A135 Paris, Sebastien ...... 371A401 Rajabi, H...... 169B152 Park, D...... 97C404 Rambaldi, Isabel ...... 371A401 Park, David S...... 146B129 Ramkissoon, Annmarie ...... 172C128 Parker, Linda A...... 47C122 174C130 Rana, Shadna ...... 47C122 Parr, Ann ...... 431B304 Rangaraj, Godha ...... 238A213 Parsadaniantz, S. Melik ...... 248A223 Rankin, Catharine Hl...... 59D109 Parsons, Matthew P...... 359A309 Rash, J.E...... 308C219 Pasquale, Elena B...... 240A215 Rathore, Khizr ...... 173C129 Patenaude, Christian ...... 300C211 Razik, F...... 416D136 Pawson, T...... 89B415 Reale, Meghan ...... 352A302 Peeling, J...... 374A404 Ren, Lei ...... 427D147 0 Peever, J.H...... 241A216 387A136 379A409 Reynolds, James N...... 4B104 Peever, John ...... 70D120 Riad, M...... 237A212 280B223 330D212 Pellegrini, Luca ...... 93B419 Riad, Mustapha ...... 251A226 Pelletier, Joe Guillaume ...... 328D210 Richard, Alby ...... 9B109

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Richards, D...... 373A403 Segal, Zindel ...... 14B114 Richelson, E...... 392A141 176C132 Séguéla, Philippe ...... 315C226 315C226 233A208 Richer, Francois ...... 153B136 168B151 Seguin, J.A...... 111C418 Riviere, J-B ...... 181C137 Seidenbecher, T...... 49C124 Rivkin, Elena ...... 81B407 Seigneur, Josée ...... 316C227 Roberts, L.E...... 384A133 18B118 Sejnowski, Terrence J...... 310C221 Robertson, Janice ...... 154B137 221D305 222D306 Seki, Tatsunoir ...... 242A217 Robertson, R. Meldrum ...... 232A207 312C223 Senatore, A...... 322D204 Robertson, R.M...... 274B217 Senzel, Anthony ...... 317C228 Robinson, Kim ...... 311C222 Seress, Laszlo ...... 285B228 Robinson, Brian ...... 137A125 Sergio, L.E...... 409D129 Rock, Erin ...... 174C130 Sergio, Lauren E...... 44C119 419D139 Roder, John C...... 92B418 Sestito, Nicole ...... 225A401 Rodgers, Corinne ...... 312C223 Shadmehr, R...... 397A146 Roedding, Angela ...... 175C131 Shahrezaei, V...... 250A225 Roky, Rachida ...... 370C310 Shalev, Uri ...... 180C136 192C148 Romano-Silva, M...... 135A123 185C141 Sharkey, Keith A...... 351A301 Romero-Pozuelo, J...... 249A224 Sharma, Rohita ...... 104C411 Rosebush, Patricia ...... 347D229 Shekarabi, Masoud ...... 181C137 Rostene, W...... 248A223 Shen, Kelly ...... 53D103 Rotzinger, Susan ...... 350D232 Shen, JK ...... 121A109 Rouillard, C...... 235A210 142A130 25B125 Sheppy, Evan ...... 182C138 Rouleau, A.G...... 181C137 Sherry, David F...... 73D123 Rouleau, Guy ...... 148B131 Shi, Xian Qun ...... 85B411 Roullet, Florence ...... 211D414 0 Shields, Lindsay E.C...... 385A134 Roussy, Geneviève ...... 176C132 Shihabuddin, Larnya ...... 234A209 Roussy, G...... 392A141 424D144 Shikatani, Eric ...... 414D134 422D142 Rubio Alvarez, Walter ...... 285B228 284B227 Shoichet, Molly ...... 430B303 94C401 434B307 Rudchenko, Aliona ...... 48C123 Shultz, Sandy ...... 183C139 Rummel, Christoph ...... 368C308 Shulyakova, Natalya ...... 369C309 83B409 Ruocco, Anthony C...... 428B302 432B305 Sidor, Michelle ...... 105C412 Russell, K.I...... 266B209 Siegel, J...... 387A136 Ruth, T.J...... 122A110 406D127 Sik, Attila ...... 275B218 Rutishauser, Urs ...... 234A209 242A217 Silasi, G...... 374A404 Ryu, Won Hyung ...... 433B306 Silver, Jerry ...... 112C419 Saab, Bechara. J...... 92B418 Silverman-Gavrila, Lorelei ...... 318C229 Sabitu, K...... 164B147 Simard, G...... 281B224 Sachewsky, ...... Nadia 102C409 Singh, Karun ...... 106C413 Sachot, Christelle ...... 368C308 Sirk, Dan ...... 254A229 Sadeghi Ghandehari, Navid ...... 413D133 Skinner, F.K...... 272B215 Saghatelyan, Armen ...... 76B402 291C202 321D203 Skinner, Frances ...... 260B203 Saint-Pierre, Martine ...... 177C133 Slack, R...... 97C404 Saint-Pierre, M...... 132A120 142A130 Slack, Ruth S...... 146B129 Saint-Pierre, Martine ...... 123A111 Smit, A.B...... 322D204 Salomonczyk, Danielle ...... 178C134 Smith, Alex ...... 319D201 Samoilova, Marina ...... 314C225 Smith, C...... 36C111 Samson, Willis K...... 360A310 367C307 Smith, Lori K...... 158B141 Sanderson, J...... 118A106 Smith, Peter A...... 295C206 320D202 320D202 Sanelli, Teresa ...... 221D305 0 Snapyan, Marina ...... 321D203 Sangha, Susan ...... 49C124 Soares, Tina ...... 422D142 Saporta, S...... 177C133 Sollenberg, ...... Ulla 320D202 Saragovi, Horacio Uri ...... 287B230 Song, Weihong ...... 184C140 200D403 Sarret, P...... 248A223 392A141 176C132 176C132 Sossi, V...... 122A110 406D127 Satvat, Elham ...... 50C125 Sossin, Wayne S. Savic, Natasa ...... 299C210 ...... 227A202 239A214 279B222 286B229 99C406 348D230 Scamvougeras, A...... 29C104 Souza, Renan ...... 185C141 Schlichter, Lyanne C...... 199D402 Spafford, J David ...... 322D204 Schmid, Susanne ...... 383A132 51D101 70D120 Spanswick, Simon ...... 290C201 Schorscher-Petcu, Ara ...... 179C135 Sparling, Joseph ...... 186C142 Schultheis, Maria T...... 432B305 Spratt, S.K...... 155B138 Scott, Christopher ...... 52D102 St.Onge, Jennifer ...... 55D105 Scott, Darcy ...... 239A214 Stanchev, P...... 29C104 Scott, S.H...... 399A148 403A152 403A152 Stanley, E.F...... 335D217 Scratch, S...... 183C139 Stanley, Elise F...... 243A218 Seabrooke, Sara ...... 103C410 Steckley, Diana ...... 214D417

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Steeves, Jennifer ...... 72D122 Tremblay, Pierre-Luc ...... 417D137 Steeves, K.E...... 26C101 Tremblay, Cyntia ...... 210D413 Stewart, Bryan ...... 82B408 323D205 Tremblay, Marie-Eve ...... 240A215 330D212 Stewart, B...... 103C410 Tribe, D.A...... 31C106 Stewart, J...... 169B152 41C116 Trudeau, Louis-Eric ...... 237A212 267B210 301C212 Sticht, Martin ...... 115A103 56D106 Tse, G...... 241A216 St-Laurent, Marie ...... 187C143 Tse, Gavin ...... 70D120 Stoessel, A.J...... 122A110 406D127 Tsien, Richard W...... 332D214 Stork, O...... 49C124 Tsotsos, Lia ...... 61D111 Strafella, Antonio P...... 30C105 Tucci, Mark ...... 115A103 56D106 Streiner, David L...... 433B306 Tuerke, Katharine ...... 193C149 Sturgess, Jessica ...... 57D107 Tung, Connie ...... 243A218 Sturm, Aliza ...... 22B122 Turner, Ray W...... 298C209 Su, Jiang ...... 92B418 Tuscan, Lori-Ann ...... 432B305 Sun, Hong-Shuo ...... 188C144 Tymianski, Michael 136A124 226A201 246A221 147B130 282B225 Sun, Yu ...... 324D206 Tymianski, Michael ...... 188C144 339D221 Sun, H.S...... 282B225 Tyndale, F. Rachel ...... 376A406 Sun, Hong ...... 147B130 Tyndale, Rachel F...... 208D411 Sun, Xiulian ...... 184C140 200D403 Tyreman, N...... 216D419 Surosky, R...... 155B138 Udina, Esther ...... 112C419 0 Sutherland, Robert J...... 290C201 Ullal, Gautam ...... 194C150 Szatmari, Peter ...... 131A119 215D418 Ungerleider, Leslie G...... 3B103 Szechtman, Henry ...... 24B124 Urushitani, Makoto ...... 113A101 Szyf, M...... 170C126 Vaccarino, Franco J...... 350D232 Tadjalli, Arash ...... 379A409 Vadakkan, Kunjumon I...... 337D219 Tai, Chao ...... 325D207 Valderrama, Ximena ...... 107C414 Tajjiou, Asmaa ...... 380A410 Valera, C...... 248A223 Tam, Alan ...... 326D208 Valyear, Kenneth ...... 418D138 Tamas, Z...... 159B142 van Adel, Michael ...... 4B104 Tan, Laura ...... 350D232 0 van der Kooy, Derek ...... 21B121 57D107 Tan, Y.F...... 400A149 69D119 Van Kesteren, Ronald E...... 262B205 Tandon, A...... 152B135 Van Leeuwen, F.W...... 224D308 Tandon, Anurag ...... 84B410 202D405 Vandamme, Katrina M...... 268B211 Tapia, Lucia ...... 327D209 Vanderluit, J...... 97C404 Tator, C.H...... 373A403 431B304 304C215 Vautrin, S...... 263B206 Tator, Charles ...... 430B303 434B307 94C401 Velumian, Alexander A...... 314C225 331D213 Tauskela, Joe ...... 189C145 Vernuri, V. Kiran ...... 351A301 Taylor, A...... 180C136 Vesia, Michael ...... 44C119 419D139 Taylor, J.E...... 191C147 Vetro, A...... 159B142 Taylor, R...... 161B144 183C139 Vette, Albert H...... 408D128 Teixeira, Cátia ...... 196C152 Vezina-Audette, Raphael ...... 124A112 Tenk, Christine ...... 74D124 0 Vilis, Tutis ...... 67D117 Tetzlaff, W...... 186C142 Volavka, J...... 185C141 Teves. Lucy ...... 188C144 Vranic, M...... 69D119 Thevarajah, Dhushan ...... 58D108 Wahab, Kolawole ...... 195C151 Thomas, Rhalena ...... 371A401 Wallace, M. Christopher ...... 217D301 Thompson, Aidan ...... 415D135 Wallman, Marie-Josée ...... 420D140 Thompson, Roger ...... 190C146 Wang, Afra Hsin ...... 196C152 Tichenoff, Lisa ...... 191C147 Wang, H...... 390A139 Timbers, Tiffany ...... 59D109 Wang, Haoran ...... 197C153 Timofeev, Igor . . . . 117A105 253A228 6B106 275B218 163B146 Wang, Haoran ...... 48C123 Timofeev, Igor ...... 45C120 316C227 344D226 Wang, Hongying ...... 394A143 38C113 Timofeeva, Elena ...... 60D110 Wang, Jian ...... 86B412 Ting-A-Kee, Ryan ...... 21B121 57D107 Wang, Jun A...... 369C309 Tirakotai, W...... 121A109 Wang, Monica (Juan) ...... 108C415 Titley, Heather ...... 416D136 Wang, Szu-Han ...... 15B115 Tjostheim, Sonja ...... 154B137 Wang, X...... 431B304 Tobin, Stephanie ...... 192C148 Wang, Y...... 266B209 Tobin, B...... 180C136 Wang, Zhiyong ...... 198D401 Tomlinson, G...... 373A403 Warre, Ruth ...... 127A115 Tootell, Roger B.H...... 3B103 Warsh, Jerry ...... 175C131 Topolnik, Lisa ...... 286B229 328D210 Wasserman, Jason ...... 199D402 Toth, C...... 343D225 Watanabe, Masayuki ...... 62D112 Toth, Katalin ...... 283B226 284B227 285B228 Weaver, Ian 109C416 ...... 170C126 Tourountzas, E...... 66D116 Webber, C...... 343D225

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Wegener, Stephen ...... 63D113 Xu, Liqun ...... 93B419 Wei, Shengcai ...... 200D403 Yakovenko, Sergiy ...... 423D143 Weinberg, J...... 266B209 Yakovenko, V...... 398A147 Weinberger, Moran ...... 201D404 Yan, Xiaogang ...... 419D139 Weiss, Sanuel ...... 80B406 Yang, Yimei ...... 338D220 Wells, Peter G...... 171C127 172C128 Yao, L.M...... 340D222 Weng, A...... 281B224 Yatham, L.N...... 122A110 Weng, Ying-Qi ...... 234A209 Ye, Hui ...... 203D406 Wentland, Kirsten ...... 314C225 Yen, Wesley ...... 144B127 West, C. Dianne ...... 131A119 Yiu, Adelaide ...... 204D407 Wetaway, D...... 152B135 Yoemans, John S...... 383A132 48C123 70D120 Wetzel, Monica ...... 110C417 Yong-Kee, Christopher ...... 223D307 0 Wheeler, Damian ...... 332D214 Yoshida, E...... 324D206 Whelan, Jennifer ...... 64D114 Young, Calvin ...... 205D408 Whelan, J...... 183C139 Young, J...... 102C409 Whitwell, Robert ...... 65D115 Yu, Wenfeng ...... 206D409 Wigg, K.G...... 159B142 Yu, Wenru ...... 207D410 Williams, John T...... 255A230 Yucel, Yeni ...... 137A125 Williams, Sylvain ...... 267B210 294C205 Yue, Jiang ...... 208D411 Wilton, Aleena ...... 66D116 Yue, J.I.T...... 69D119 Winick, Warren ...... 333D215 Yum, Jennie ...... 339D221 Winter, Rebecca ...... 421D141 Zahir, Tasneem ...... 434B307 Wiskerke, Joost ...... 354A304 Zahir, T...... 431B304 Wislet-Gendebien, Sabine ...... 202D405 Zamponi, Gerald W...... 244A219 273B216 Witelson, S.F...... 29C104 52D102 Zelnickova, P...... 276B219 Wojtowicz, J.M...... 69D119 329D211 Zerradi, Mouna ...... 370C310 Wolf, Marla E...... 65D115 Zettel, John ...... 67D117 Wollaston, Lori ...... 211D414 Zhang, Tie Yuan ...... 68D118 Wong, Adrian ...... 334D216 Zhang, Wen-Jia ...... 69D119 Wong, Fiona ...... 335D217 Zhang, Guangming ...... 217D301 Wong, Teser ...... 422D142 Zhang, Ji ...... 85B411 Wong, A...... 185C141 Zhang, Liang ...... 260B203 307C218 182C138 203D406 Wong, Albert H.C...... 129A117 135A123 Zhang, Zhuohua ...... 184C140 Wong, T...... 266B209 Zhao, WG ...... 121A109 Wong, Teser ...... 414D134 Zhao, Xiaoli ...... 268B211 Wood, JodiAnne T...... 351A301 Zheng, WenHua ...... 340D222 Woodin, Melanie ...... 309C220 336D218 Zhou, Lei ...... 341D223 Woodside, B...... 180C136 Zhou, Ning ...... 342D224 Woody, Erik ...... 24B124 Zhou, Weihui ...... 184C140 Wright, Lisa ...... 42C117 Zhou, Yu ...... 116A104 Wright, Melissa ...... 371A401 Zhu, Wenjun ...... 209D412 Wu, Long-Jun ...... 337D219 Zhuo, Min ...... 337D219 Wu, Chiping ...... 182C138 307C218 Zisch, Andreas ...... 341D223 Xiao, Shangxi ...... 222D306 221D305 Zochodne, Douglas ...... 343D225 XiaoDong, Guo ...... 434B307 Zomorrodi Moghaddam, Reza ...... 344D226 Xiaogang, Yan ...... 394A143 Zomorrodi, Reza ...... 253A228 Xiaotang, Fan ...... 227A202 Zunino, Rodolfo 93B419 Xiuquing, Chen ...... 233A208

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